CURRICULUM VITAE ET STUDIORUM OF PAOLO LENISA
Born in Udine on 06/17/65
Studies
- 1992 Degree in Nuclear Engineering from Politecnico di Milano with 100/100 cum laude.
- 1997 PhD in Physics at the University of Ferrara with “excellent” judgment.
Professional Positions
- 1997 - 1999 Guest scientist at the Max-Planck Institute in Heidelberg.
- 1999 - 2014 Researcher at the University of Ferrara
- 2014 - 2017 Associate Professor in Experimental Physics at the University of Ferrara
- 2017 - Professor in Nuclear and Subnuclear Physics at the University of Ferrara
CONTENTS:
• PART 0: SUMMARY
• PART I: SCIENTIFIC ACTIVITY
• PART ll: ADMINISTRATIVE AND MANAGEMENT ACTIVITY
• PART III: ORGANIZATIONALY ACTIVITY
• PART IV: TEACHING ACTIVITY
• PART V: LIST OF PRESENTATIONS AT CONFERENCES, MEETINGS, SCHOOLS
SUMMARY
Scientific Activities
Main current:
- Development and management of polarized targets.
- Production and application of polarized beams of antiprotons.
- Applications of the technology of polarization to hadronic physics: study of the structure of the nucleon.
- Study of the form factors of the proton.
- Applications of the technology of polarization on the fundamental physics: measurement of the electric dipole moment of the proton and deuteron, Time Reversal Invariance
- Polarized fusion
Main previous activities:
- Design and development of photocathodes with negative electron affinity.
- Laser cooling of ions in storage rings.
Main scientific results
- First demonstration of the application of an innovative wide band laser to laser cooling of an ion beam in a storage ring.
- First measurements of the spin-exchange collisions cross section at low temperature.
- First direct measurement of the helicity of the valence quarks and quark s.
- First experimental evidence of the transversity and of a non-zero angular momentum of the quarks in the proton (Collins and Sivers effects).
- Demonstration of non-applicability of the mechanism of spin-flip to the polarization of a beam stored in a storage ring.
- Demonstration of the polarizability of beam stored in a storage ring by spin-filtering.
Main national and international scientific responsibilities
- 2000 – 2005 Coordinator of the management group of the polarized target experiment HERMES (DESY-HH).
- since 2004 Co-spokesperson of the International Cooperation PAX
2005 Proponent as co-spokesperson of the PAX experiment at the new facility FAIR in Darmstadt, Germany.
- 2007-2008 Ideation preparation and management as Spokesperson of a measure of depolarization of a beam of protons at the ring COSY to FZJ-Jülich
- 2008 Co-proponent and team leader for Ferrara of OLYMPUS experiment at DESY in Hamburg for the measurement of two-photon contribution to the form factors of the proton.
- 2009 proponent acting Spokesperson of the measurement of the spin-dependence of the cross section at the ring proton antiproton AD CERN.
- 2008-2011 Planning, preparation and management as Spokesperson of a measure of spin filtering at the COSY ring.
- 2011 proponent acting Spokesperson of a measure of the coherence time of spin-longitudinal at the ring COSY.
- 2012 Co-proponent collaboration and co-responsible for the PAX experiment TRIC for a test of invariance at the COSY ring of the FZ-Jülich
- 2012 Co-proponent and responsible for the group of Ferrara experiment JEDI for the measurement of the electric dipole moment of the proton and deuteron at the ring COSY of the FZ-Jülich
Main administrative and managing national and international responsibilities.
- 2003 - 2005 Responsible for the research unit of Ferrara for PRIN 2003 project approved and funded by MIUR: "Study of SIDIS reactions ep -> e'hX for the analysis of transversality of the nucleon."
- since 2005 National responsible of the PAX experiment at the Group III-INFN
- 2006 - 2008 Responsible for the research unit of Ferrara for PRIN 2006 project approved and funded by MIUR: "Study of transverse spin in the nucleon through semi-inclusive DIS reactions ep -> e'hX, Drell-Yan processes pbar p -> l + l-and pbar p elastic scattering. "
- 2007-2010 Scientific Officer for the University of Ferrara of the Virtual Institute of European institutions funded by the Helmholtz-Gesellschaft: "Virtual Institute on Spin and Strong QCD".
- 2008-2011 Scientific responsible for the unit of Ferrara of the Joint Research Activity "Hard-Exclusive Reactions (Hardex)", Work Package 23 of the project "Hadron Physics 2" (I3HP2) funded by the European Commission within the VII Framework Programme.
- 2008-2011 Scientific responsible for the unit of Ferrara of the Joint Research Activity "Polarized antiprotons (PolAntiP)", Work Package 25 of the project "Hadron Physics 2" (I3HP2) funded by the European Union under the Seventh Framework Programme (Grant Agreement 227431).
- 2009 -2012 Responsible for the Research Unit of Ferrara PRIN for 2008 project approved and funded by MIUR: "Study of transverse spin in the nucleon through semi-inclusive DIS reactions ep -> e'hX, Drell-Yan processes p pbar -> l + l-and pbar p elastic scattering. "
- 2009-2013 Scientific coordinator of the collaborative project between the University of Ferrara and the Forschungszentrum - Jülich entitled "Spin-filtering studies in Storage Rings" for the financing of joint doctoral and post-doctoral students. Contract No. 41853505 (FAIR-009).
- 2010-2015 Scientific responsible for the unit of Ferrara Advanced Research Grant "POLPBAR" financed by the European Council resarch within the VII Framework Programme (Grant Agreement no. 246980).
- since 2011 member of the International Spin Physics Committee
- 2012 - 2014 Scientific responsible for the unit of Ferrara of the Joint Research Activity "Polarized antiprotons (PolAntiP)", Work Package 25-part of the Project "Hadron Physics 3" (I3HP3) funded by the European Union under the Seventh Framework Programme .
- since 2012 Coordinator of the Section of Ferrara in the National Scientific Committee III INFN
- 2013-2014 Scientific coordinator of the collaborative project between the University of Ferrara in collaboration between the Forschungszentrum - Juelich entitled "Spin-tracking studies in Storage Rings" for the financing of joint doctoral and post-doctoral students. Contract No. 42028694 (FAIR-021).
Conducts Referee for the following journals:
- Nuclear Instruments and Methods
- Europhysics Journal.
- Radiochemical Acta
Since 2005 is member of the Teaching Committee for PhD in Physics from the University of Ferrara.
Main organizational responsibilities
- 2005 Co-organizer of the International Workshop on "Transverse Polarization Phenomena in Hard Processes" (Como, 7-10 September 2005)
- 2006 Co-organizer of the second "Caucasian-German School and Workshop on Hadron Physics" (Tbilisi, Georgia, 4-8 September 2006)
- 2007 Co-organizer of the Workshop "ANKE / PAX Workshop on Spin-Physics," Ferrara May 29-June 1, 2007
- 2007 Co-organizer of the workshop "Hard QCD with antiprotons at GS-FAIR", ECT, Trento, Italy, 16-20 July 2007
- 2008 Chairman of the Workshop "Transversity 2008 - 2nd Workshop on Transverse Polarization Phenomena" Ferrara, 28-31 May 2008
- 2008 Co-chairman of the Workshop "Polarized antiprotons" Bad-Honnef (Germany) 24-26 June 2008
- 2009 Chairman of the Workshop: PST2009 - XIII International Workshop on Polarized Sources, Targets and Polarimetry, Ferrara, Italy, 07-11 September 2009
- 2011 Co-organizer of the Workshop "STORI11, 8th International Conference on Nuclear Physics at Storage Rings", Frascati, Italy, 9-14 October 2011
- 2013 Co-chair of the International School of doctorate "Niccolo’ Cabeo": "Physics beyond the standard model: the precision frontier", Ferrara, Italy, 20-24 May 2013
Teaching activity
- 1999 to 2000 General Physics II Course for the Master of Science in Civil Engineering
- 2001 Course of General Physics I for the Degree in Civil Engineering
- 2005 Cycle of lectures to the XV Study Days on the detectors at Villa Gualino (TO), (Course for graduate students) entitled "Polarization in storage rings"
- 2002 to 2008 General Physics I Course for the Master of Science in Civil Engineering
- 2007 to 2008 General Physics II Course for the Master of Science in Civil Engineering
from the 2009 Course of General Physics for Civil Engineering
Supervisor of 5 PhD in Physics
Supervisor of 8 thesis in Physics
Scientific publications
- Author of over 150 articles, more than 100 of which on international journals with referee.
- Signatory of 11 proposals for experiments and letters of intent including 7 as Spokesperson.
- Curator of the Proceedings of the 4th International Conference.
Public presentations
- He has presented at 33 conferences and congresses (32 international) of which 14 by invitation.
Dissemination activities
- Since 2012 is part of the editorial staff of the website of scientific INFN "Science for all"
Other information
- Fluency in written and spoken English.
- Fluency in written and spoken German.
- Basic knowledge of the Russian language.
PART I: SCIENTIFIC ACTIVITY
Brief summary and guidelines.
Paolo Lenisa was trained as atomic physicist, contributing as a graduate student a graduate student first and later as a guest scientist at the Max-Planck-Institute in Heidelberg, to the study of an innovative laser source for the cooling of a stored ion beam in storage rings. Among the experimental results, it is worthwhile of mention the first experimental evidence, obtained at the ring TSR of Heidelberg, of the effectiveness of the use of an innovative broad-band laser in the cooling of a beam of ions [PRL 80 (1998) 2129]. The result proves unambiguously that such type of source is able to counter the intrabeam-scattering phenomenon representing the dominant mechanism of heating of the longitudintal phase space of the stored particles.
Paolo Lenisa was the winner of the competition as a researcher at the University of Ferrara in 1998. His training as a atom-physicist and experience on storage rings allowed him to fit naturally in the management group of the polarized internal target experiment HERMES (DESY-Hamburg) in which he played the role of coordinator from 2000 to 2005. HERMES, which concluded its data-taking in 2007, and was a Depp-Inelastic Scattering experiment, which used internal gaseous hydrogen and deuterium targets, longitudinally and transversely polarized hydrogen, positioned on the electron/positron beam in the HERA storage-ring at DESY-Hamburg (Germany). Under the direction of Paolo Lenisa, the target has stabilized its performance allowing the group to publish 10 articles on international journals [NIMA 482 (2002) 606, EPJD 18 (2002) 37, NIMA 508 (2003) 268, NIMA 482 (2002) 1, NIMA 505 (2003) 633, NIMA 496 (2003) 277, NIMA 496 (2003) 263, EPJD 29 (2004) 21, NIMA 540 (2005) 68, EPJD 48 (2008) 343]. Among these, mention has to be deserved to a couple of measurements related to atomic physics that were stimulated and developed thanks to the expertise of Paolo Lenisa: the first measure of remnant polarization of molecules obtained by recombination of an inert surface [EPJD 29 (2004) 21] and the first measurement of the spin-exchange collision cross section between hydrogen atoms at low temperature [EPJD 48 (2008) 343].
The excellent performance of the target, allowed the HERMES to play a key role in the international community in the study of the spin structure of the proton and deuteron. In particular, the analysis of the semi-inclusive asymmetries collected in 1996-2000 with longitudinally polarized hydrogen and deuterium, has enabled the HERMES Collaboration to measure for the first time in a direct way the longitudinal polarization of the valence quarks u and d and s quark the sea [PRL 92 (2004) 012005, PRD 71 (2005) 012003]. Confirming the indications of the indirect inclusive measurements, the polarization of the u-quark was positive with greater polarization in large x where the quark valence dominate, while the polarization of the d-quark is negative. The measurements also show that the polarization of the sea quarks is small. Taken together, all these measures, stimulated by the so-called "spin crisis" of the late '80s, show conclusively that the spin of the quarks generates less than half the spin of the proton and that the only contribution comes from those of quarks value.
The following data taking with transversely polarized hydrogen target (2002-2005), has allowed HERMES to play a pioneering role in the study of spin and transverse momentum distributions in the nucleon. This study is crucial for understanding the structure of the proton and its importance is underscored by the funding of three dedicated research PRIN projects by MIUR (Italian Ministery of University and Research), of which Paolo Lenisa is responsible for the research unit of Ferrara (PRIN 2003, PRIN 2006 , PRIN 2008). The funding made it possible to support the members of the group in the data analysis of HERMES. We mention in particular the extraction of Sivers and Collins amplitudes, both measured with unpolarized beam and transversely polarized hydrogen target [PRL 94 (2005) 012002, PRL 103 (2009) 152002, PLB 693 ( 2010) 11]. These two azimuthal amplitudes contain information on fundamental parton distribution functions of which little was known before. The first, called Sivers function, describes the correlation between the transverse momentum of the quarks and the transverse polarization of the nucleon. The second, called transversity, is related to the number density of transversely polarized quarks within a transversely polarized nucleon. HERMES has provided the first experimental evidence that both transversity and the Collins fragmentation functions are not null. It also provided the first experimental evidence that the Sivers function itself is non-zero, implying the existence of a non-zero orbital angular momentum of quarks in the nucleon, hitherto never measured. The azimuthal asymmetries detected by HERMES combined with those of the COMPASS at CERN and the measurement of the Collins function at BELLE (KEK, Japan) made it possible to carry out the first extraction of the transversity distribution of the nucleon, a result that represents a milestone for hadron physics. At the same time, the measurements of the Sivers’ amplitudes, has been recently allowed the extraction of the Sivers function for the u and d quarks u and d, obtaining, for the two flavors, values approximately equal in absolute value and opposite in sign. This result, in agreement with predictions can be phenomenologically interpreted as evidence of the fact that, inside the proton, u and d quarks have orbital angular momentum of opposite sign.
The acknowledgement in the international community for his expertise in the technology of polarization in storage rings and interest in the study of the structure of the nucleon, have allowed Paolo Lenisa to promote as Co-Spokesperson, the International Collaboration PAX (Polarized Antiproton eXperiments) and to submit in 2005 a Technical proposal to the FAIR facility at GSI in Darmstadt [http://www2.fz-juelich.de/ikp/pax/portal/documents/proposals/files/techproposal20060125.pdf]. This proposal is linked to possible experimentation with the first ever antiproton beam intense polarized.
To support the proposal, Paolo Lenisa has in recent years studied the mechanism of polarization of a nucleon beam of nucleons circulating in a ring, both from the theoretical and the experimental points of view [94 PRL (2005 ) 014 801, PLB 674 (2009) 269, PLB 718 (2012) 64, http://www2.fz-juelich.de/ikp/pax/portal/documents/proposals/files/proposal20071020.pdf, http://www2.fz-juelich.de/ ikp/pax/portal/documents/proposals/files/proposal20080414.pdf, http://www2.fz-juelich.de/ikp/pax/portal/documents/proposals/files/proposal20090426.pdf]. Despite the many existing proposals, before the experimental activity promoted by Paolo Lenisa, only one experimental evidence existed related to a spin-filtering test of protons, carried out at the ring TSR in Heidelberg in 1992.
In principle, there are two possibilities to polarize a beam of particles of spin ½, as antiprotons, stored in a storage ring. The first, called "spin-flip", is based on the existence of a mechanism that gives rise to a different transition probabilities between up and down states with respect to the opposite process. The second, called "spin-filtering", involves the use of a process that selectively removes one state over the other from the ring. Paolo Lenisa has promoted, implemented and carried-out a series of measurements devoted to the understanding the mentioned mechanisms. A first measurement has allowed to provide the experimental demonstration of the ineffectiveness of the technique of spin-flip [PLB 674 (2009) 269], leaving spin-filtering as the only perspective for the “in-situ” polarization of a stored beam of antiprotons. A second measurement has proven the effectiveness of the filtering mechanism in spin to polarize a beam stored in a storage ring. The measurement is of fundamental importance for the field of research. It has in fact confirmed the recent theoretical understanding of the mechanism of polarization filtering, subject of controversial theoretical interpretations in the past. It has also allowed (as proof of the perfect control of all the experimental systematic effects) the extraction of the proton-proton polarizing cross-section [PLB 718 (2012) 64]. As acknowledgment of the importance the research, the European Union has funded the mentioned studies by an Advanced Research Grant (POLPBAR: 2010-2015), of which Paolo Lenisa is scientific responsible for the University of Ferrara and two Joint-Research Activities in the Projects Hadron Physics 2 (2008-2011) and Hadron Physics 3 (2012-2014) of which Paolo Lenisa is scientific responsible for the INFN of Ferrara.
In order to study the applicability of the spin-filtering technique to the polarization of antiprotons, the PAX Collaboration, led by Paolo Lenisa, has developed and submitted in 2009 a Technical Proposal to the CERN-SPS Committee devoted to the measurement of the spin dependence of the proton-antiproton cross-section [http://www2.fz-juelich.de/ikp/pax/portal/documents/proposals/files/proposal20090426.pdf]. The precise knowledge of this cross section is necessary for the design of a dedicated polarizer storage ring. The existing theoretical predictions for this cross section, reflect the uncertainty of the description of the annihilation proton-antiproton process and disagree by almost a factor of 2, making and experimental measurement indispensable. The AD ring at CERN is the only machine in the world capable of storing antiprotons in an energy range favorable to spin filtering (between 50 and 500 MeV).
Giving continuity to the expertise gained in the technology of polarization in storage rings, Paolo Lenisa has recently oriented his interest in applications related to fundamental physics measurements. In this framework, have to be inserted a test of time invariance at the COSY ring and the measurement of the electric dipole moment (EDM) of proton and deuteron in a storage ring of new generation. These measurement of interest for the exploration of physics beyond the Standard Modal, represent an important application for the knowledge in polarization technology, unique in Italy, acquired over the years by Paolo Lenisa, and his research group. In this regard, Paul Lenisa, has submitted proposals for dedicated experiments to the Physics Advisory Committee of COSY [http://www2.fz-juelich.de/ikp/publications/PAC40/176.6-Ed-sum.pdf, http:// www2.fz-juelich.de/ikp/publications/PAC40/EDM-COSY-Proposal_cover_23.04.2012.pdf, http://www2.fz-juelich.de/ikp/publications/PAC40/215-TRI_Prop_sum.pdf], as responsible of the Ferrara group, one of which as Spokesperson. For further details, please refer to the detailed description of the activity.
We finally mention a recent activity in which Paolo Lenisa is involving his group, which is also related to the technology of polarized targets. Paolo Lenisa is promoter of a scientific collaboration agreement between INFN Ferrara, the Nuclear Physics Institute - PNPI (Gatchina, Russia) and the FZJ (Jülich, Germany) for the study of fusion reactions of light elements with polarized initial particles. The project aims at measuring the cross section and angular distribution of the products of the nuclear fusion reactions D + D and D +3 He in the energy range 10-100KeV. This measure, besides presenting physical interest in itself, is linked to the possibility of using polarized deuterons as a fuel for thermonuclear fusion plants. The contribution of the group of Ferrara is related t the atomic polarized source. It is expected to move a polarized atomic source, presently in Ferrara, to the Laboratory of Gatchina by the end of 2012. After a period of adaptation of the source and commissioning of the entire experimental setup, the beginning of the data taking is expected in 2014.
PERSONAL CONTRIBUTIONS AND CHRONOLOGY
- Development of innovative cooling techniques with a laser beam (1994-1998)
The research carried out as part of the doctoral thesis has been the development of new cooling and diagnostics techniques of stored ions by means of laser beams. Laser cooling is the most effective method of cooling of an ion beam in the longitudinal phase and makes use of the radiation pressure generated by a laser beam resonant with a closed transition between two energy levels of the stored ions. Paolo Lenisa was proponent of an innovative method of laser cooling able to improve the cooling efficiency. The greatest obstacle to the longitudinal laser cooling of ions in a storage ring is the phenomenon of internal collisions (intrabeam-scattering). The coulomb binary collisions between the particles of the beam are able to transfer part of the kinetic energy of the transverse degrees, which are not affected by the laser cooling, in the longitudinal one, bringing the ions outside the velocity capture range of the spontaneous force and making them effectively lost for the cooling cycle. The proposed idea is to use a so-called "white laser", i.e. a laser with a large spectral width, compensating for the Doppler shift and enabling ions with different velocities to be simultaneously resonant with the radiation. Paolo Lenisa has collaborated to the development of the first ever laser with broad spectrum (500 MHz) completely controllable in intensity and frequency. A test of the developed source and proposed technique has been successfully performed at the storage ring TSR of Heidelberg and has demonstrated the effectiveness of the technique to counteract the effect of Coulomb collisions between particles. The exposed arguments have been the subject of the doctoral thesis discussed at the University La Sapienza of Rome, with unanimous opinion of the Commission "excellent", on 7/17/97 with the: "Development of new cooling techniques and diagnostic laser to a beam of ions stored in a storage ring".
From 04.97 to 08.98 Paolo Lenisa was guest-scientist at the Max-Planck Institut fuer Kernphysik in Heidelberg, where he continued the testing activities of techniques for cooling of ions in a storage ring.
- Coordinator of the polarized target HERMES experiment at DESY in Hamburg (2000-2005).
The HERMES experiment (HERa Measurement of Spin), mainly devoted to the study of spin structure of the proton, has been in operation on the storage ring HERA at DESY in Hamburg from 1995 to 2007. The HERMES spectrometer detects the events generated by deeply inelastic scattering of polarized electron or positron at an energy of 27.5 GeV polarized off a polarized internal target. Besides identifying inclusive events, the HERMES spectrometer is provided with a RICH detector, with a double radiator able to distinguish pions, kaons and protons and a spectrometer capable of detecting up to 14 charged tracks fillers, allowing semi-inclusive and exclusive analysis.
From 1996 to 2005 HERMES employed an internal polarized hydrogen/deuterium target. The orientation of target spin has been assured by the application of an external magnetic field, that had longitudinal direction up to 2000 and has been changed to traverse in 2001. The polarized target was dismantled in 2005 to host a large acceptance recoil detector. The target has been realized through a beam of polarized atoms that after being produced by a source atomic were injected into a storage cell which was an integral part of the vacuum tube of the ring itself; atoms diffusing towards the open ends of the cell, were then removed by an efficient pumping system. In order to limit the phenomena of recombination and depolarization due to collisions of atoms with the walls, the storage cell was coated with an inert polymeric material based on silicon (Drifilm) [NIMA 496 (2003) 277]. A sample of gas from the cell, diffusing through a second side tube, was analyzed by a quadrupole mass spectrometer to determine the atomic fraction and a Breit-Rabi polarimeter to measure the atomic polarization [NIMA 482 (2002), 606].
Paolo Lenisa has served as coordinator of the target group in the period 2000-2005. The management group of the target involved an international collaboration of physicists including besides the University of Ferrara, the University of Erlangen, Monaco and Madison, collaborators from MIT in Boston and the University of Novosibirsk.
In the long data taking period, the HEREMS target, only in high-energy physics to adopt this sensitive technology, has gone from being a craft to fully professional, as evidenced by the stability of the data collected and the reduction of systematic errors [see for example NIMA 540 (2005), 68]. Exactly with the purpose of documenting this technological progress, that a careful description of the different parts of the apparatus and the subject of physics involved in the operation of the target has been undertaken, work which led to the publication 10 articles on international journals [NIMA 482 (2002) 606, EPJD 18 (2002) 37, NIMA 508 (2003) 268, NIMA 482 (2002) 1, NIMA 505 (2003) 633, NIMA 496 (2003) 277, NIMA 496 (2003) 263, EPJD 29 (2004) 21, NIMA 540 (2005) 68, EPJD 48 (2008) 343].
An additional problem in the management of a target such as the HERMES one, involving a period of several years of data taking, was represented by the need to reconcile the requirements of the experiment with the ones of the operators who were Diploma and PhD students and needed arguments for the theses. For this reason, in parallel to the data taking of HERMES, a series of interesting atomic physics measurements have been performed and published, made possible by the systematic control and appropriate use of the ductility of the target. These works are briefly described below.
One of these is represented by the first measurement of the nuclear polarization of recombined hydrogen molecules on an inert surface, like the one represented by the Drifilm-coated storage cell. This measurement was performed using the double-spin asymmetry in the cross section of polarized electron- polarized proton collision (called A_1), in particular exploiting the independence of the interaction between elementary virtual photon and the quark in a proton belonging to an atom or a molecule. The originality of the approach comes from the use of a spectrometer of high energy physics for a delicate measurement of surface physics. The result was the topic of the PhD thesis of which Paolo Lenisa has been tutor and published in an international journal [EPJ D 29 (2004) 21]. The application of the measurement to the data collected with polarized Hydrogen, has allowed a reduction of the total systematic error of such data by almost 50%.
Another atomic physics measurement performed with the HERMES target, was the first measurement of the spin-exchange collisions cross section between hydrogen atoms at low temperature (50 K-100 K). The measurement, of interest in astrophysics, has been made possible thanks to the ductility of the target of HERMES that allows the injection into the cell and subsequently detection of any combination of hyperfine states of the hydrogen atom, and also offers the possibility to vary the temperature of the gas by varying the temperature of the cell. The execution of the measure required the complete control of the complex target systematics and was performed without affecting the ordinary data taking of the experiment. The results were the subject of the PhD thesis of which Paolo Lenisa was tutor and has been published in international journals [EPJ D 48 (2008) 343].
Finally it should be mentioned that the experience gained and the contacts with the American University of Madison and Argonne, allowed to transfer the complex and delicate production technique and coating of the cells from the laboratory of the University of Wisconsin-Madison to the mechanical workshop of the University and INFN of Ferrara, which took responsibility for the design and production of the storage cells accumulation both HERMES in the period 1998 to 2007, and for the present OLYMPUS experiment (see next paragraph).
In 2000-2005 data taking period the HERMES target has collected about 20 million polarized DIS events. Of these, the over 10 million events collected with longitudinally polarized deuterium are still the best existing sample from the point of view of statistical and systematic error on the polarization measurement. The 6 million events collected with a transversely polarized hydrogen target were the first sample of the kind ever.
- Selection of some experimental results HERMES experiment.
The production of the HERMES experiment covers a wide spectrum in the field of hadronic physics and spin in particular. In the following we present some results linked to data taken with the polarized target in which the group coordinated by Paolo Lenisa have given a substantial contribution from both the experimental point of view, as in the case of the management of the polarized target, or of the data-analysis, as for the case of transverse data.
- Deep inelastic scattering with longitudinally polarized target.
In the period 1996-1997, HERMES has collected about 3 million events of Deep Inelastic Scattering (DIS) with a longitudinally polarized hydrogen target. This statistic, has enabled to determine the structure function g_1p (x) of the proton with an accuracy comparable to that of the most precise existing measurement performed at SLAC by the experiments E143 and E155 [PRD 75 (2007) 012 007]. The results of HERMES extend to x-values lower than those of SLAC, in a region so far only covered by the SMC experiment and are in perfect agreement with those of the previous experiments. The function g_1p (x) has a positive sign and is maximum around values of x ~ 1/3 that characterize the region of the valence quarks. In association with the so-called u-quark dominance of the proton (consisting of two u-quarks and a single d-quark, weighed with the square of the charge in cross section), this result reflects the tendency of u-quark to be positively polarized (Delta u> 0), that is, to be parallel oriented with respect to the spin of the proton.
Based on more than 10 million DIS events collected with a longitudinally polarized deuterium target in 1998-2000, HERMES was able to perform the most precise existing measurement of the g_1d(x) structure function of the deuteron. In a similar manner to g_1p (x), also the structure function g_1d (x) has a maximum around the region of values of x ~ 1/3, but its modulus is lower. An analysis of this result, taking into account the composition of the valence quarks of the deuteron, indirectly highlights the tendency of the d-quark to be negatively polarized (Delta d <0), that is to be oriented anti-parallel to the spin of the proton. In the region at low x (x <0.04), the data of HERMES are compatible with 0, in agreement those of COMPASS, while the data of SMC favor g_1d <0.
Overall, HERMES has added new and more precise data in its kinematic domain to the experiments of first and second generation, in particular for the deuterium target. It is also important to note that the data of HERMES (as well as those of SLAC), were collected at transferred momenta significantly lower than those of previous experiments such as EMC and SMC. This has allowed to perform a comprehensive analysis of the behavior of the polarized structure functions for the whole of the world's data through techniques of perturbative QCD. These analyzes have allowed, besides the indirect derivation of the polarization of quarks of different flavor, also an estimation for the upper and lower limits of the gluon polarization.
The deuteron is a spin-1 object of spin-1 and to fully describe its structure at leading-order level, an additional structure function is required besides to the two describing the proton, namely the so-called b_1 structure function. This is linked to nuclear effects and would disappear if the deuteron consisted simply of a proton and a neutron in a state of relative s-wave. HERMES is the only DIS experiment where it was possible to implement a target that presented tensor polarization, with which it was possible to measure b1 [PRL 95 (2005) 242 001]. The measured value for b_1 has proved be small, but not zero and can be interpreted as a result of the same mechanism that leads to the effect of shadowing in the case of unpolarized deep-inelastic scattering. In practice, the virtual photon is sensitive to the spatial relative alignment of proton and neutron and interacts with the proton interacts first and then with the neutron.
- Semi-inclusive deep-inelastic scattering with longitudinally polarized target.
The main disadvantage of the inclusive reactions is that they are sensitive only to the square of the charge of the quark, but are independent from its flavor and consequently provide only information related to the sum of the spin of the quarks. In order to obtain information regarding the contribution to the spin of the nucleon for each flavor of quarks, it is necessary make use semi-inclusive deep-inelastic scattering reactions (SIDIS) in which, in addition to the lepton, also some of the particles generated in the process of hadronization are detected. The quark which absorbed the virtual photon leaves the nucleus and fragments into hadrons. The observation (of part) of these hadrons can be used as a filter to identify the flavor of the original quark (technique of flavor-tagging). The analysis of the semi-inclusive asymmetries collected in the period 1996-2000 with longitudinally polarized hydrogen and deuterium, has enabled the HERMES collaboration to measure directly for the first time the longitudinal polarization of the u and d valence quarks and of sea quarks s [ PRL 92 (2004) 012005, PRD 71 (2005) 012003]. Confirming the indications of the indirect inclusive measurements, the polarization of the u-quark was positive with greater polarization in large x where the quark valence dominate, while the polarization of the d-quark is negative. The measurements also show that the polarization of the sea quarks is small. Taken together, all these measures show conclusively that the spin of the quarks generates less than half the spin of the proton and that the only contribution comes from the valence quarks.
-Semi-inclusive deep-inelastic scattering with transversely polarized target: transversity
The transverse-spin distribution h_1 is the last piece of the description of the nucleon structure description at leading order: h_1 measures the difference in probability of finding a quark polarized in a direction parallel to the polarization of a nucleon transversely polarized with respect to the direction of motion. It has not been measured directly, as it is a "chirally-odd", and is not accessible through inclusive deeply inelastic scattering. The density h_1 can be extracted from measurements of the spin-asymmetries in the cross-section SIDIS processes between leptons and polarized nucleons in which is a hadron in the final state is detected. In these processes, the measured asymmetry is due to the combined effect of h_1 and another chirally-odd function that describes the process of fragmentation of transversely polarized quarks (the Collins fragmentation function H_1perp .
The HERMES data taking with a transversely polarized hydrogen target, began in 2002 and ended in 2005. The group of Ferrara, thanks also to the support of three approved PRIN-grants, of which Paolo Lenisa was local responsible, was involved in decisive way in the data analysis. The collected statistics has allowed the study of azimuthal asymmetries in the production of pions and kaons. The detected asymmetries are related related to two effects. In addition to the mentioned contribution of the convolution between the transversity distribution h_1 and the Collins fragmentation function, there is a contribution by the Sivers distribution function, linked to a correlation between the transverse polarization of the nucleon and the intrinsic transverse momentum of the quarks. It indicates that the momentum of transverse quark can no longer be neglected in the leading description of the interactions and indicates that the orbital angular momentum of the quarks is different from zero. With the aid of a transversely polarized target, the mechanisms of Collins and Sivers can be separated, because they have different azimuthal dependencies azimuthal with respect to the axis of the transverse polarization. HERMES has published the first single spin asymmetries in the production of hadrons from a transversely polarized target [PRL 94 (2005) 012002, PLB 693 (2010) 11]. The data of HERMES have allowed for the first time to establish that both the processes originating the Collins and the Sivers asymmetries are nonzero. As regards the Collins process, the average momenta moments resulted positive for pi+ and negative for pi- qualitatively in agreement with models that, in analogy with the density of helicity Delta u and Delta d, foresee positive delta u and negative delta d. The azimuthal asymmetries revealed by HERMES in combination with those of the COMPASS experiment at CERN and the results from the BELLE experiment, have allowed to perform the first extraction of the transversity distribution function for u and d quarks, a result that can be considered a milestone for the spin physics.
The observation of Sivers asymmetries [PRL 94 (2005) 012002, PRL 103 (2009) 152002] non-zero was the first direct experimental evidence of a quark orbital angular momentum is not zero. Although a complete and comprehensive interpretation of all the measured asymmetry is not yet available, the data collected allowed the first extraction of the Sivers function for u and d quarks giving indication that the quarks u rotate in agreement with the spin of the proton, while the d quarks rotate in the opposite direction.
- Proponent as co-spokesperson of the PAX experiment at the new facility FAIR in Darmstadt, Germany (2004-2006)
Lenisa Paolo is co-author, as Co-spokesperson of the PAX (Polarized Antiproton eXperiments) experiment proposal for the new FAIR facility at GSI in Darmstadt [hep-ex/0505054]. At the base of the PAX proposal is the possibility of realizing the first intense beam of polarized antiprotons through the technique of spin-filtering in a storage ring.
The availability of a beam of polarized antiprotons would allow the measurements of a series of single and double-spin of asymmetries of spin single and double spin that would allow to access for the first time different physical quantities. For example, such a beam would allow access to the transversity distribution function in a direct and complementary way to the SIDIS measurements. In fact, the azimuthal asymmetries in Drell-Yan pair production generated in the annihilation of transversely polarized protons and antiprotons transversely polarized, depend exclusively on the product h_1 x h_1 and allow its direct measurement. The asymmetry is expected to be of the order of 20-30% in the region where the valence quarks dominate. In addition to the aforementioned transversity function, by measuring the single and double spin- azimuthal asymmetries in the production of lepton pairs from proton-antiproton annihilation the magnitude and phases of the proton electromagnetic form factors of the proton in the timelike region can be derived. Of particular interest is also the study of the role of the spin in the double spin asymmetries in elastic proton antiproton collisions. Such measurement could assist in the interpretation of the asymmetries measured in elastic proton-proton collisions with double polarization which are still lacking a proper theoretical explanation.
The proposal has awaken considerable interest in the international hadronic physics community and received the consent of about 200 physicists belonging to 35 institutions (20 of which are European) that have signed the Letter of Intent sent to the Directorate of GSI in January 2004, followed in January 2005, by the Technical Proposal.
As Spokesperson, Paolo Lenisa followed all aspects of the proposal, especially the issues related to accelerators. Given the complexity of the project, it was necessary to form a real working group dedicated to the machine development. The group included accelerator physicists from Jülich, BNL and Dubna with experience both in the field of polarization and in the colliders.
The implementation of the proposed measurements should be carried out in two stages corresponding to the stages of the system of accelerators. The first phase involves an experiment in which the polarized antiprotons, after production in a dedicated polarizer ring, are stored in another ring, accelerated up to a momentum of 3.5 GeV/c and then made to collide on a polarized internal gas target. The kinematic conditions offered by this solution are ideal for the study of form factors and elastic collisions. A ring of these characteristics has been identified in the ring COSY, currently in operation at the FZJ in Jülich, which will be decommissioned after 2015. The second phase involves the construction of an asymmetric proton-antiproton collider with double polarization. The storage of antiprotons and protons in the COSY and HESR rings respectively, planned for the FAIR facility with a maximum momentum of 15 GeV/c, would result in collisions with an energy in the center of mass energy of about sqrt (s) ~ 15 GeV, which is ideal for the study of transversity.
The long timeline of the experiment and the necessary priority given to the complete understanding of the process of polarization of antiprotons. finalized in a series of dedicated experiments presented below, have limited the study of the detector at the level of conceptual design. Fundamental element of the detector is represented a toroidal magnet which present zero field along the axis of the beam and allows in the first phase of the experiment the use of an internal target polarized with the possibility of directing at will the magnetic axis of quantization.
The physics program of the PAX experiment was judged as excellent by the Program Advisory Committee of the FAIR facility. However, the implementation of the PAX experiment within the facility was subject to the demonstration of feasibility of the proposed technique to produce polarized antiprotons: the spin-filtering. The confirmation of the polarizability of a stored proton beam by spin-filtering, and the demonstration that this mechanism as the only able to polarize the nucleons accumulated in a ring has been recently achieved with a series of experiments dedicated realized ring COSY the FZJ-Juelich. Paolo Lenisa is one of the promoters of this series of experimental initiatives related to the study of the mechanisms of production of a beam of polarized antiprotons. His activity 'in this field is briefly reported below. In the framework of his collaboration with the COSY-Juelich FZJ Lenisa Paolo Lenisa has acted as Spokesperson of an International Collaboration.
- Ideation preparation and management as Spokesperson of a depolarization measurement of a beam of protons at the COSY storage ring at FZJ-Jülich (2007-2008).
Two possible principle ways exist to polarize a beam of a spin 1/2 particles, as antiprotons, stored in a storage ring. The first, called "spin-flip" is based on the existence of a mechanism that gives rise to a different transition probabilities between up and down states with respect to the opposite process. The second, called "spin-filtering", involves the use of a process that selectively removes from the storage ring one state with respect the other.
This framework justifies a depolarization measurement of a beam of protons, performed at the COSY-storage ring of the Forschungszentrum Juelich in 2008. The experiment was motivated by the possibility of experimentally proving a proposal of an innovative method to polarize an antiproton beam by making use of the spin exchange interaction with a polarize co-moving positron beam (technique of spin-flip). This proposal was put forward by a group of physicists at the University of Mainz in 2007. Despite the limited intensity for a polarized positron beam obtainable with current technology, the proposal was of interest for the high cross sections of spin-exchange calculated by the proponents (> 10^13 barn). The method offered itself to a favorable experimental evidence at the COSY ring. With respect to the proposal, in the performed experimental test, both the charge of the two beams have been reversed (protons and electrons were used instead of antiprotons and positrons), and the role of the beams themselves. In the measurement, use has been made of the principle that if the transfer mechanism is active to transfer spin polarization from an initially polarized positron (electron) - beam to an initially unpolarized antiproton (proton) - beam, then the same mechanism must be active to depolarize an initially polarized antiproton (proton) - beam by interaction with an initially unpolarized positron (electron) - beam. The COSY ring offered the ideal experimental conditions for carrying out such a test, having at disposal polarized proton beams and an electron cooling system capable of producing a beam of unpolarized electrons with the possibility of varying in a controlled way the relative velocity between the electron and proton beams.
The limited energy range of the COSY electron cooling system, has driven the execution of measurement at the injection energy of the proton beam (45 MeV). The measurement cycle itself has been organized into two phases. In the first phase, that of depolarization, the electron beam has been alternately tuned and de-tuned in energy with respect to the proton beam. Such alternation had the aim of avoiding to degrade the characteristics of the proton beam in the depolarization phase. The theoretical estimates included in fact a cross section maximum (and therefore the maximum effect of depolarization) for relative kinetic energies between the proton and electron beams of about 2 keV. In this condition, the electron beam ceases its cooling function and the proton beam begins to heat up. In order to avoid this effect, the time of detuning of the electron beam with respect to the nominal energy has to be limited. A preliminary test performed in November 2007, prior to the measurement made in February 2008, has allowed us to determine the ideal time for the alternation of the two beam energy conditions in intervals of 5 seconds. In the second phase of the measurement cycle, the beam polarization was measured using by making use of the single-spin asymmetries generated in elastic scattering of the proton-beam off a deuterium target. For this purpose use has been made of the cluster-target of the ANKE experiment. In order to reveal the left-right asymmetry in the recoil deuteron, a system of two telescopes realized by silicon detectors has been installed. The positioning of the detector has been determined by optimizing the figure of merit of the diffusion reaction (square of the product of the analyzing-power times the cross section), while the thickness of the silicon detectors (300 microns) has been chosen so to ensure the identification of deuterons from protons. Implementation of the detector has been handled by the Juelich group. The Ferrara electronic workshop, under the coordination of Paolo Lenisa, contributed to the commissioning of the readout electronics (Paolo Lenisa is Tutor of dedicated PhD thesis) and of the development trigger-board successfully used during the measurement.
The measurements itself showed no effect of depolarization of the beam within the statistics acquired during the experiment. The negative outcome resulted in the expression of an upper limit to the spin-transfer cross section related to the depolarization effect effect. This limit was set at 5 x 10^7 barn which makes the proposed method not applicable, also considering possible future technological developments in the intensity of the sources of polarized positrons. The measure has been the subject of publication in an international journal [PLB 674 (2009) 269].
Paolo Lenisa, besides having taken care of the scientific aspect of the experimentation, has been active in searching for the financial support of the activity. The Italian component of the collaboration has been supported besides by INFN (Paolo Lenisa is the national scientific responsible for the PAX experiment), by a Joint Research Activity (I3HP2) funded by the European Union for the period 2008-2011. Part of the Work-Package (WP 25: PolAntiP) of the JRA, for which Paolo Lenisa is local responsible, was actually motivated by the mentioned depolarization studies. With the funds of the financing, the unit of Ferrara has supported three annual grants dedicated to the development of the experimental apparatus and analysis of the collected data.
- Design, preparation and management as Spokesperson of a of spin-filtering measurement at the COSY ring (2009-2011).
The experimental demonstration that the spin-flip technique could not be used to polarize a stored antiproton beam, has left as the only option the use of the spin-filtering mechanism. For this reason, in April 2009, Paolo Lenisa as Co-Spokesperson of the PAX Collaboration, has promoted a spin-filtering experiment with protons at the COSY-ring in Juelich. Aim of the measurement was twofold: to confirm the theoretical knowledge of the spin-filtering mechanism on the one hand, and to commission the experimental apparatus for a possible subsequent test with antiprotons on the other.
The preparation phase of the measurement had a duration of nearly three years, that have been used to install and commission the required experimental apparatus inside the ring COSY. The interaction region devoted to a spin-filtering experiment consists of three basic elements: a) a set of quadrupole magnets for the realization of a low-beta section where to install the storage cell with the polarized gas; b) a polarized internal target with its polarimeter and c) a beam polarimeter.
The magnets used for the realization of the interaction point were recovered from the decommissioning of the CRYRING-ring at Stockholm. For the realization of the target, use has been made of the apparatus of the HERMES experiment, properly updated, while the beam polarization was measured by the asymmetry in the elastic scattering events detected by a couple of silicon-telescopes managed by the ANKE Collaboration, and previously used for the depolarization experiment.
An important phase of the experiment commissioning was devoted to accelerator studies and improvement of its performance. In the context of a spin-filtering experiment and the final polarization induced in the beam, a key parameter is the average beam lifetime. Thanks to a series of dedicated machine studies and improvements of the vacuum conditions of the ring, the average beam lifetime has been improved by a factor greater than 20, bringing it to a value of tau = 8000 s which was the one used in measurement. (A dedicated paper is in preparation).
The spin-filtering test with protons has been finally performed in the Autumn 2011. Aim of the experiment was the measurement of the spin dependence of the proton-proton cross section in the case of transverse polarization. To this aim a dedicated spin-filtering cycle has been implemented in the ring. As first step, an unpolarized proton beam is injected in the ring, the beam is then cooled (by electron cooling) and accelerated to the energy of the measurement. At this point the polarized target is "switched-on" and the spin-filtering process starts. The duration of this phase, amounting to 1.5 – 2 beam lifetimes, has been determined to optimize the statistic for the following phase of the experiment: namely the measurement of the beam polarization. Finally, the polarized target is switched-off, and, in another section of the ring, an unpolarized deuterium target is “switched-on". The polarization induced in the beam is measured through the identification of elastic scattering events by means of a pair of silicon telescopes.
Combining the induced polarization in the beam with other information such as the polarization and density of the target, and the revolution frequency of the particles in the ring, it was possible to determine the polarized interaction cross-section polarized in the case of transverse proton-proton interaction. The result is in excellent agreement with the theoretical predictions and represents a milestone for the concerned research. On the one hand confirming the current understanding of the spin-filtering process and on the other demonstrating a complete control of the ' experimental apparatus and its systematic uncertainties.
As Co-Spokesperson of the PAX Collaboration, Paolo Lenisa followed and directed all phases of the experiment from the proposal, to the organization of the Collaboration, the commissioning of the apparatus, the performance of the measurement and, finally, the analysis of collected data. The experience and knowledge gained by Paolo Lenisa during the HERMES experiment, allowed the use of some of the resources of this experiment that completed its data taking in 2007. In particular, the polarized target and its polarimeter were transported in Juelich and put into operation after an appropriate update. From the organizational point of view, several working groups have been established engaged in the different design and implementation activities. In addition to the three cited: target, detector and accelerator, additional working groups were formed around the activity related to data acquisition, control and analysis of the collected data and their theoretical interpretation. Each working group was managed by a coordinator. The responsibilities of the various groups were distributed according to the competence of the various institutes of the collaboration taking part to the experiment: in addition to Ferrara and Juelich, these include also Bari, Dubna, Erlangen, Mainz, St. Petersburg, for a total of about 50 "active" participants. In addition to through regular meetings, the coordination of the activity of Collaboration has been accomplished by the extended use of teleconferencing (via Skype) and the introduction of a wiki page to facilitate the exchange of documents and information between the different groups (http://apps.fz -juelich.de/pax/paxwiki/index.php/Main_Page).
The work is described in the three dedicated publications dedicated: one devoted to theoretical calculations, one to the machine preparatory studies and one dedicated to the measurement itself (accepted for publication on Phys. Lett B). Paolo is Lenisa is tutor of two doctoral theses related to the preparation and the implementation of the measure.
Paolo Lenisa, besides having taken care about the scientific aspect of the experimentation has been active in fundraising for the financial support of the activity. The Italian component of the collaboration has been supported besides by INFN, by an Advanced Research Grant (POLANTIP) funded by the European Research Council for the period 2010-2015 of which Paolo Lenisa is scientific responsible for the unit of Ferrara. As part of this project 5 post-doc grants and 3 contracts for technical collaboration have been funded through the University of Ferrara.
- Proponent as Co-Spokesperson of the measurement of the spin-dependence of the proton-antiproton cross section at the AD ring at CERN AD (2009).
Simultaneously with the submission of the proposal of the spin-filtering experiment with proton at the COSY ring, the PAX Collaboration has submitted a Technical Proposal to the CERN SPS Committee to make the first measurement of the spin dependence of the proton-antiproton cross section. Such knowledge would allow the design of a dedicated a storage ring to polarize an antiproton beam through spin-filtering. The current theoretical predictions for the spin dependence of the proton-antiproton cross section, are dominated by the uncertainty in the description of the annihilation process and are conflicting with each other by a factor 2, which requires a direct measurement. The AD ring at CERN is the only machine in the world which presents an energy range favorable to filtering spin with antiprotons (between 50 and 500 MeV).
The PAX Collaboration has proposed the installation of the experimental apparatus for the measurement, in one of the four straight sections of the ring. In the drafting of the proposed experiment, particular attention was paid to the compatibility with the experiments already operating on the AD ring and performing delicate measurements related to antimatter. For this reason, the planning foresees an installation of the experimental apparatus divided into three phases, the success of each of which constitutes the necessary condition for the transition to the next. The first phase involves solely the installation of additional quadrupoles in a straight section of the ring for the realization of a low-beta section, without altering the existing magnetic structure. Once ensured the reproducibility of the performance of the machine for the other experiments with use of the new quadrupoles, one should switch to the next installation step comprising the removal of the existing quadrupole placed at the center of the straight section to make room for the scattering chamber of the PAX experiment. Only in the last and third phase, foresees the installation of the experimental apparatus. This includes: a polarized atomic source, a storage cell, surrounded by a silicon telescopes detector to measure the beam polarization a the Breit-Rabi polarimeter to measure the target polarization. Currently, the proposal is being considered by the Committee at CERN SPS which is evaluating the impact on the programming and testing that has already been approved at the AD ring.
- Co-proponent and team leader of Ferrara of the OLYMPUS experiment at DESY in Hamburg for the measurement of two-photon contribution to the proton electromagnetic form factors.
Some measurements of the proton electromagnetic form factors carried out at the JLAB Laboratory (Virginia, USA) in the early 2000 through the polarization transfer technique, showed an unexpected and dramatic discrepancy with the measurements made by the well-established Rosenbluth unpolarized cross-section separation technique. The discrepancy could be explained by introducing the exchange of more photons in the calculation of the elastic electron-proton cross section over the traditional single-photon approximation. An experimental confirmation of this theoretical interpretation is very important since most of the present understanding of the structure of the proton and of atomic nuclei relies on the diffusion of leptons analyzed through single photon approximation.
For this reason, in September 2008, the OLYMPUS Collaboration has submitted an experimental proposal to the Physics Research Committee of DESY in Hamburg. The OLYMPUS Collaboration, of which Paolo Lenisa is scientific responsible for the unity of Ferrara, consists of 50 physicists from Germany, Italy, Russia, United Kingdom and United States. The experiment aims to measure accurately the ratio of the cross sections for elastic collisions between positron-proton and electron-proton. The most direct evidence for a multi-photon exchange is inferred by the deviation from the unit of this ratio. The experiment uses the intense beam of electrons and positrons of the DORIS ring incident with an energy of 2.0 GeV on a target of molecular hydrogen stored in a storage cell placed in the beam line. The detector of the experiment is constituted by the large acceptance toroidal spectrometer of the BLAS experiment, (MIT-Boston, USA). After the completion of the installation in 2010-11 and the successfully completed commissioning in early 2012, the experiment will acquire two months of dedicated data taking in winter 2012. The ultimate goal is the measurement of the ratio of cross sections with an accuracy better than 1%.
The Participation of Ferrara to the Collaboration has been specifically requested by the other members of the Partnership, some of which were previous members of the HERMES experiment, thanks to the acknowledged competence of the group of Paolo Lenisa in the realization of the storage cells. Such a device, realized through a properly shaped sheet of aluminum with a thickness of 75 microns, is one of the most delicate points of the whole experimental apparatus, especially in a hard environment such as that of an electron storage ring.
- Co-proponent of an experiment for the measurement of the electric dipole moment of the proton and deuteron in a storage ring and Spokesperson of a measure of the longitudinal spin-coherence time of a polarized beam at the COSY storage ring.
Giving continuity to the skills acquired in the control and management of systematic involved in polarized beams Paolo Lenisa has recently devoted his interest to a proposal of measurement of the electric dipole moment (EDM) of the proton and deuteron in a storage ring [C.10]. A intrinsic non-zero EDM in these particles would violate both parity P and time-reversal symmetry, which, assumed CPT invariance, would give an indication of CP violation. It is well established that the CP violation sources in the standard model are not sufficient to explain the matter-antimatter asymmetry in the universe and the search for mechanisms of CP violation is one of the frontiers of the new physics. The predictions of the standard model for the electric dipole moment of particles such as the proton and deuteron are well below the measurable experimental limit, the situation is different for the predictions of models of physics beyond the standard model that are well inside the experimental reachable sensitivity.
The search for an EDM in a storage ring is a relatively recent and is strictly linked to the technological developments of polarization in storage rings themselves. The measurement technique involves the injection in the ring of a beam longitudinally polarized along the direction of the velocity of the beam itself. Through a particular configuration of electric and magnetic fields in the ring, it is possible to inhibit the precession of the spin of the particle with respect to the momentum (condition of "frozen-spin"). In this condition, the signal of an EDM different from zero is represented by the precession of the polarization direction from longitudinal to vertical, under the influence of a strong electric field in the reference system of the beam itself. At a level of sensitivity of around 10^(-29) e cm, the signal of the EDM would be represented by a precession of the order of 10^(-5) rad after a storage time of 20 minutes. The observation of this small change in the polarization of the beam requires a number of conditions. A fundamental requirement is that the polarization of the beam remains high during the 20 minutes requested to accumulate a measurable signal. The availability of polarized beams of protons and deuterons and of the related polarimetry, makes the ring COSY a unique environment to study the influence of various parameters of the beam on the polarization lifetime. For this reason, a dedicated program has been initiated to study the effect of various parameters of the lifetime of the longitudinal beam polarization, or, more properly on the spin-coherence time. In this context, Paolo Lenisa is co-Spokesperson of a program of measurements devoted to the determination of the spin-coherence time at the COSY ring. One of the effects that we intend to study the influence of the synchrotron and betatron oscillations of on the spin-coherence time and the possibility of compensating for these effects through the use of radiofrequency cavites and sextupoles.
- Co-proponent and responsible for the PAX Collaboration of the TRIC proposal for a test time-reversal invariance at the COSY ring of the FZ-Juelich
Unlike the search for an intrinsic electric dipole moment, the existence of which would violate simultaneously both parity and time invariance, the TRIC (Time Reversal Invariance at COSY) experiment is aiming to test the time-invariance (Time Reversal Invariance, TRI) in a situation in which the parity is preserved. An observable on which to perform such verification has been identified in the proton-deuteron spin-correlation A_(y,xz) in which the vector polarization of the proton P_y is oriented along the y direction and the tensor polarization of the deuteron P_xz, according to the direction xz.
This test offers itself to a favorable experimental verification inside a storage ring. In fact, using the property of parity conservation of the variable under observation, the verification may be performed by comparing the total transmission cross sections of a polarized proton beam stored in the ring through a internal polarized deuterium target. A difference in the total cross sections of interaction of the beam with the target obtained by reversing the direction of one of the two polarizations, would constitute an indication of time-invariance violation. That statement is immediately translated into a different lifetime of the stored beam, and the experiment can be practically traced to a precise measurement of the beam current into the storage ring.
Particularly attractive is the situation at the COSY ring, where the measurement can be realized with the complete re-use of the experimental apparatus developed for the PAX-experiment PAX (target and relative polarimeter implemented with a large acceptance detector for the determination of the beam polarization). The experiment also will benefit of the machine studies performed by the PAX collaboration that led the ring to its present excellent performance with regard to the beam lifetime and polarization. The only important additional implementation to existing apparatus, is constituted by a high-precision beam current monitor. In order to achieve the necessary accuracy, from which the accuracy of the entire measurement depends, the plan is to make use using cryogenic current comparators employing the SQUID technology.
After a feasibility study carried out in late 2012, the experiment foresees to start dedicated data taking in 2015, when the large acceptance detector will be completed and the new beam current monitor installed in the COSY ring.
- Promoter of a scientific cooperation agreement between INFN Ferrara, the Nuclear Physics Institute (PNPI), Gatchina, Russia, and the FZJ (Juelich, Germany) for the study of fusion reactions of light elements with polarization of the initial particles .
Paolo Lenisa is the promoter of an agreement for scientific collaboration between INFN Ferrara, the Nuclear Physics Institute (PNPI), Gatchina, Russia, and the FZJ (Juelich, Germany) for the study of fusion reactions of light elements with polarization of the initial particles.
The project aims to extensively study the differential cross section of the reactions d + d -> t + d and d+d -> n-3He with polarized incoming deuterons in the energy range 10-100 keV. In particular the aim is to study the influence of the polarization vector and tensor on the total fusion cross-sections and the branching ratio of the two channels. A direct experimental measurement is quite important given the discrepancy between the different theoretical predictions. The study is also important from the point of view of the possible applications of advanced fusion power-plants employing polarized particles. An increase of the polarized reaction to the non-polarized, would allow a reduction in the size of the vessel, at the moment in which density of polarized particles comparable with the unpolarized case could be reached. In addition, a different branching-ratio in the fusion two channels, such as the suppression of the neutron channel as predicted by many theoretical works, would decrease the damage by neutron radiation and allow for an extension of time of operation of the future generation of fusion reactors.
The experimental apparatus involves the use of a beam of polarized deuterons accelerated to a suitable energy incident on a polarized atomic deuterium target. The reaction products will be analyzed using a large acceptance detector realized with silicon diodes. As part of the collaboration, the deuteron source is provided by the German part of the collaboration, while the Russian side is providing the detector. The contribution of Ferrara consist in the polarized atomic source. It is expected to move the atomic source presently located in the Ferrara Labs to Gatchina by the beginning of 2013. After a period of adaptation of the source and commissioning of the entire experimental setup, the data taking is expected to start in 2014.
PART ll: ADMINISTRATIVE ACTIVITY AND MANAGEMENT
In order to provide the necessary financial support to its research team and the appropriate scientific framework of his group in the national and international research community, Paolo Lenisa has become promoter and coordinator of various projects related to funding requests at national and international level.
At the Italian national level, Paolo Lenisa, since 2005, the national scientific responsible of the PAX-experiment inside INFN. He was also coordinator for Ferrara of three research projects PRIN (2003, 2006, 2008) funded by the Ministry of Education dedicated to the study of transversity of the nucleon. At the international level, Paolo Lenisa was and still is responsible for the University of Ferrara of three work packages of the Joint Research Activities - I3HP2 and I3HP3 and of an Advanced Research Grant financed by the European Commission within the VII Framework Programme, linked to research on polarized antiprotons.
- 2003 - 2005: Responsible for the research unit of Ferrara of the PRIN 2003 project approved and funded by MIUR: "Study of SIDIS reactions ep -> e'hX for the analysis of transversality 'of the nucleon."
Paolo Lenisa was responsible for local project PRIN - 2003 approved by the Ministry of Education in 2003 dedicated to the theoretical and phenomenological investigation of transversality of the nucleon. The project involved theoretical and experimental physicists of the Italian universities of Como, Ferrara, Trieste and Turin, involved in the experiments HERMES and COMPASS. To the Research unit of Ferrara belonged physicists and graduate students of the University of Ferrara and the National Laboratories of Frascati.
The transverse spin distribution h_1 is the last missing piece in the partonic description of the nucleon aat leading order: h_1 measures the difference in probability of finding a quark polarized in a direction parallel and opposite to the polarization of a nucleon transversely polarized with respect to the direction of motion. The h_1 distribution function has never been directly measured, since it is a "chirally-odd" fnction, and is absent in inclusive deeply inelastic scattering. The density h_1 can be extracted from measurements of cross section spin-asymmetries in semi-inclusive deeply inelastic scattering processes (SIDIS) of leptons and transversely polarized nucleons which also reveals a hadron in the final state. In these processes, the measured asymmetry is due to the combined effect of h_1 and another chirallly-odd function, which contributes to the fragmentation of transversely polarized quarks. In the case in which the final observed hadron is a pion or, in general, a scalar particle, this new function of fragmentation is the so-called Collins, and, at the time of the project, not yet measured. The HERMES data taking with a transversely polarized hydrogen target began in 2002 and ended in 2005. The collected statistics has allowed the study of non-zero azimuthal asymmetries with transverse target. These asymmetries, that the Unit of Ferrara has significantly contributed to analyze, are related to two effects. The first, represented by the distribution of Sivers, is related to a correlation between the transverse polarization of the nucleon and the intrinsic transverse momentum of the quarks. It indicates that the transverse momentum of the quark can no longer be neglected in the leading description of the interaction and indicates that the orbital angular momentum of the quarks is different from zero. The second effect is due to the convolution between the transversity distribution h_1 and the Collins fragmentation function that relates the transverse momentum of the leading hadron to the spin of quarks that produced it. Both functions were not measured at the time of the project. The measurements performed with the transverse target made it also possible to quantify the contribution of higher-order twist to the azimuthal asymmetries measured with longitudinal target.
The financing of about 70 keuro was used to fund three research annual grants devoted to the analysis of the HERMES data.
- 2006 - 2008 Scientific responsible for the research unit of Ferrara for the PRIN 2006 project approved and funded by MIUR: "Study of transverse spin in the nucleon through semi-inclusive DIS reactions ep -> e'hX, Drell-Yan processes pbar p -> l + l-and pbar p elastic scattering. "
The new aspect of the PRIN project submitted and approved in 2006 compared to 2003 is the proposal to unambiguously measure h_1 linked to the PAX experiment. The PAX proposal, "Polarized Antiproton Experiments", is part of the "Facility for Antiproton and Ion Research" (FAIR) of a large European laboratory for the study of hadronic physics planned at Darmstadt. The proposal is based on the possibility to obtain for the first time a high-quality beam of polarized antiprotons, for the study of transverse spin effects of the nucleon through Drell-Yan (DY) processes and pbar-p elastic scattering. The Drell-Yan pbar p -> e+ e- is a complementary approach with respect to SIDIS that allows a direct and unique measurement of transversity distribution function and to verify the change of sign foreseen for the Sivers-function compared to DIS. The use of an internal polarized target similar to that of HERMES one internal to the beam line and the creation of a pbar p-polarized collider will allow to detection for the first time of double polarized Drell-Yan reactions. The spin asymmetries in this case depend only from h_1 and do not require the concomitant presence of another chirally-odd quantity: h_1 appears twice in the reaction, one for each interacting nucleon. Transverse polarized DY can be studied also in RHIC (Relativistic Heavy Ion Collider) at Brookhaven National Laboratory, but only in proton-proton reactions of high energy. In this case the transverse spin asymmetries depend on the convolution of two different transversity functions – h_1 (quark) and h_1 (antiquark), measured in the region of low x-Bjorken where they are expected to be very small (of the order of 0.01). In contrast, PAX uses antiproton-proton reactions where the asymmetries depend on the simple product of h_1 (quark) with itself, and plans to explore the energy region of the valence quarks, where the asymmetry and large (of 'order of 0.3).
The working project of the Ferrara research unit, coordinated by Paolo Lenisa, was expected to contribute to some of the most promising HERMES analysis in different channels of semi-inclusive DIS, which at a theoretical level, are supposed to be sensitive to transversity, and also to provide feasibility studies and optimization in preparation for the future measurement of the PAX experiment, as ideal continuation of the present research.
The total funding of 60 keuro was used for the funding of two annual research grants devoted to the analysis of the HERMES data and the simulation of Drell-Yan events in double polarized proton-antiproton annihilations.
- 2010 - 2012 Scientific responsible for the research unit of Ferrara for teh PRIN 2008 project approved and funded by MIUR: "Study of the effects of spin and transverse momentum in the nucleon through semi-inclusive DIS reactions ep -> e'hX, processes of Drell- Yan pbar-p -> l+ l- and pbar-p elastic scattering. "
The activity of theoretical and phenomenological investigation of the PRIN 2003 and 2006 was revived with success in 2008. Indeed, despite the enormous progress in the latest years, there are still many unclear points about the internal spin-structure of hadrons and polarized fragmentation functions, related to non-perturbative properties of hadrons, that cannot be calculated in perturbative quantum chromodynamics (pQCD) but which can be estimated through phenomenological models or experimentally measured.
Of the three basic distributions that characterize at leading-order, the state of the quarks in the nucleon, the unpolarized distribution is known with great accuracy, the helicity distribution (longitudinal spin) has been measured with good precision, but in a limited kinematic range, while the transverse spin distributions, as the transversity h_1, have not yet been directly measured, although experimental information indirect start to be available. These results allowed a first extraction of h_1
The study of transverse spin effects in the nucleon has shown that the transverse component of momentum (transverse momentum) can no longer be neglected in the description of the interactions; the non-trivial correlations between the transverse components of the momentum and the spin generate unexpected effects that can open new scenarios on the internal dynamics of the nucleon and described by new transverse momentum - dependent partonic functions (TMDs). The new time-reversal odd (T-odd) correlation functions are sensitive to transverse spin effects that currently subject of great interest. The fragmentation functions, such as those sensitive to the quark polarization, are not only indispensable for the extraction of transversity h_1 in semi-inclusive DIS reactions, but are also of great interest in itself, because they describe the process of hadronization, or in other words, the origin of the quarks’ confinement.
Of great importance are the new T-odd parton distributions, such as the Sivers functions that relate the transverse momentum of the quarks to the spin of the nucleon to which they belong and therefore involve the orbital angular momentum of partons, or the Boer-Mulders functions that correlate momentum and transverse spin of quarks in unpolarized nucleons and involve the spin-orbit partonic effects.
In the framework of the MIUR project, the activities of the research unit of Ferrara, is oriented to the study of transverse spin distributions and the corresponding fragmentation functions of the nucleon, the finalization of the most promising HERMES analysis in different channels of semi-inclusive DIS, that at the theoretical level are considered to be sensitive to transversity and TMDs, and finally to a contribution to the approved experiments at Jefferson Lab with a beam of 6 GeV, relevant to this type of investigation.
The total funding of 50 keuro was used for the funding of two annual research grants annual dedicated to the conclusion of the data analysis undertaken within the HERMES experiment.
- Since 2005: National scientific responsible for the PAX experiment in the INFN National Scientific Committee III
In order to provide financial and logistical support to the activity of the PAX Collaboration, Paolo Lenisa requested and obtained the opening of a code for the PAX-experiment in the Commission III INFN. Paolo Lenisa, since 2005, is the national (and local Section of Ferrara) responsible for the PAX experiment. At the PAX experiment pertain researchers from Ferrara and Bari – INFN sections. Over the period 2005-2012, the PAX-INFN code has always had an annual average of ten full-time equivalent related.
The INFN contribution was crucial both for the Italian participation and for the overall management of the experiment. In the dual role of Co-spokesperson of the PAX Collaboration and national scientific responsible inside lNFN, Paolol Lenisa was able to coordinate the contribution of INFN synergistically with that of the rest of the Collaboration, represented mainly by the German Forschungszentrum Juelich. While the contribution of the FZJ has been finalized to developments related storage ring, the Italian INFN funding was mainly focused on relevant issues more related to the experimental apparatus. In particular, it should be mentioned:
- Moving, updating and implementation of the polarized target and the Breit-Rabi polarimeter of the HERMES experiment at DESY in Hamburg to Forschungszentrum-Juelich. Ferrara is responsible for managing the polarimeter within the Collaboration. In collaboration with the Section of Bari a new interlock and slow control system for the polarimeter based on LabView has been designed and implemented.
- Design and implementation of a new trigger system for the PAX experiment. Thanks to the work of the Ferrara electronic workshop a new trigger board has been designed, built and commissioned to replace the existing obsolete system at the FZJ based on NIM modules.
- Development of a test bench for Silicon detectors in Ferrara. This system includes a vacuum chamber offering the option to perform energy calibrations of the detectors.
- Design of a large-angle detector for the future activity of the Collaboration and prototyping activities of the key components (eg cooling).
- Contribution to the purchase of silicon detectors to complete the construction of the detector that foresees also the reuse of some silicons from the recoil detector of the HERMES experiment.
- Purchase of electronic boards for the detection system
In total, including support for travel costs, the INFN contribution of the experiment overcomes the million euro over a period of six years.
- 2007 – 2010 Local scientific responsible of Virtual Institute of European universities funded by the Helmholtz-Gesellschaft: "Virtual Institute on Spin and Strong QCD".
Lenisa Paolo was responsible for the research unit of Ferrara for the Virtual Institute "Spin-physics and Strong QCD" funded by the Helmholtz Gesellschaft. The Virtual Institute is composed by 7 universities and research institutes of Europe (Germany, Italy, Switzerland, Poland) which are centers of excellence in the field of hadronic physics and spin. The Institute was supposed to support such research by granting international travels of the physicists involved in the research, both theoretically and experimentally. The obtained financing, 60 keuro in three years, has made it possible to offer substantial support for the participation of foreign physicists, especially students, to two workshops organized in Ferrara where Paolo Lenisa acted as Chairman Lenisa ("Transversity 2008" and "PST2009" described later). The grant also allowed to finance the stay at the University of Ferrara of foreign researchers involved in the research.
- 2008-2011 Scientific responsible for the unit of Ferrara of the Joint Research Activity "Hard-Exclusive Reaction (Hardex)", Work Package-23 in the framework of the Project "Hadron Physics 2" (I3HP2) funded by the European Community within the VII Framework Program.
Lenisa Paolo was scientific responsible for the INFN Ferrara of Work-Package 23 in the JRA I3HP2 (Coordinator Carlo Guaraldo) funded by the European Community. The work package collected European physicists from different institutions involved in several, taking data and future experiments (HERMES, COMPASS, PANDA, JLAB). The purpose of the project was the management of a coordinated action of the various experiments dedicated to the study of exclusive reactions as a tool to access the Generalized Parton Distributions of the Nucleon (GPDs). Task of the unit of Ferrara was to investigate the possibility of installing a polarized hydrogen target in the PANDA experiment planned to be installed in the HESR ring at the future FAIR facility. Such an experimental situation, would allow the access to different physical observables via single-spin asymmetries in proton-antiproton annihilations. Among the possible measurements, worthwhile to be mentioned is the phase of the proton electromagnetic form factors in the time-like region. The installation of a polarized target in the detector of the PANDA experiments represents a particularly difficult task, due to the presence of the solenoidal magnet. that, in the absence of adequate measures, limits the state of polarization of the target to the longitudinal direction.
The total support of about 60 kEuro has been used to support a two-year research grant for the study of a suitable configuration of magnetic fields providing the proper shielding of the solenoid with a counter-solenoid. At the same time we studied the possibility of realizing the containment field of the target, through the use of high-temperature superconducting magnets installed on the support of the storage cell of the polarized target.
- 2008-2011 Scientific responsible for the unit of Ferrara of the Joint Research Activity "Polarized antiprotons (PolAntiP)", Work Package 25 of the project "Hadron Physics 2" (I3HP2) funded by the European Union under the VII Framework Programme .
Lenisa Paolo has been scientific responsible for the INFN Ferrara of the Work-Package 25 (PolantiP) in the JRA I3HP2 (Coordinator Carlo Guaraldo) funded by the European Community. Aim of the activity was to support the activity developed at the COSY ring, related to the production of polarized antiprotons. In particular, two were the objectives of the project: the studies of depolarization of a beam of polarized protons by interaction with an unpolarized electron beam (described earlier), and the a spin-filtering test to polarization of a stored proton beam (also previously described). Both objectives were successfully completed within the timeframe of the project.
The total funding of about 60 keuro was used to fund two research grants dedicated to the development of acquisition electronics of the experiment and to fund travel expenses of members of the group in Germany.
- 2012 - 2014 Scientific responsible for the unit of Ferrara of the Joint Research Activity "Polarized antiprotons (PolAntiP)", Work Package 25 of the project "Hadron Physics 3" (I3HP3) funded by the European Commission within the VII Program framework.
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The project represents the continuity of the one completed in the previous three years. Goal is the completion of studies on proton spin-filtering with a measurement obtained with a longitudinally polarized target. This measurement is justified both from the point of view of physics involved (the interaction cross sections for transverse and longitudinal polarizations are independent of each other) that from that of the involved technology. In fact, the spin-dynamics of a longitudinally polarized stored beam is completely different from that of a vertically polarized beam, moreover also the measurement of the polarization induced in the beam requires a different type of detection technique.
For a proper synergic coordination of the various financial supports to the activity, most of the amount of the fund (about 60 keuro) has been assigned to the travel expenses (particularly at the ring COSY) for the Ferrara group.
- 2010-2015 Scientific responsible for the unit of Ferrara for the Advanced Research Grant "POLPBAR" financed by the European Research Council within the VII Framework Programme.
The research activity on the production polarized antiprotons has received a further important recognition by the European Research Council, represented by the acknowledgement of an Advanced Research Grant for a total funding of 2.5 Meuro. Purpose of the Grant is to support the spin-filtering with protons at the COSY and those on antiprotons at the AD ring at CERN. The measurement of the transverse polarizing cross section has been successfully completed in the first phase of the project and that in the next future will include a measurement with longitudinal polarized target at the COSY-ring. For the possible measureents with antiprotons at the AD ring is necessary to wait for the reply of the CERN SPS Committee to the PAX Proposal. Principal Investigator of the Proposal is prof. Hans Stroeher, director of the 'Insitute fuer Kernphysik II of the Forschungszentrum Juelich. In addition to the unit of Ferrara, partner in the project is the Laboratory for Nuclear Physics in Dubna.
The financing for the research unit of Ferrara, coordinated by Paolo Lenisa, is of approximately 600 keuro. The funds were crucial to finance the labor force of the project. Within the five years of the project, this will involve the funding of 10 Post-Doc annual grants and 4 contracts for technical cooperation.
PART III: ORGANIZATIONAL ACTIVITY
To support and disseminate in the scientific community his line of research, Paolo Lenisa has promoted and organized various International Schools and Workshop, three of them as Chairman, two of which were held in Ferrara. In the following we describe the contributions to the main ones. The full list can be found in the introduction to this CV.
- Co-chairman of the 409.WE Heraeus-Seminar: "Polarized antiprotons" - Bad-Honnef, Germany, 23 - 25 June 2008 (http://www.fe.infn.it/heraeus/
Paolo Lenisa organized as Co-chairman the Seminar "-Polarized antiprotons" that was held at the Physik-Zentrum Bad-Honnef in Germany 23 to 25 June 2008. The Workshop was organized with the aim to explore the potential applications of polarized antiprotons in the field of hadronic physics and at the same time to point out of the current status on the possible mechanisms involved in the production of a beam of polarized antiprotons both form the experimental and theoretical points of view. For this purpose the workshop hosted the leading international experts in the field. The workshop was also an opportunity of training for young students and researchers with an interest in nuclear and hadronic physics. The event was organized with the support of the German foundation Heraeus and was attended by about fifty European physicists. Paolo Lenisa, as co-chairman, was responsible for both the organization of the scientific program and for the logistics of the Workshop.
- Chairman of the Workshop: "Transversity 2008 - 2nd Workshop on Transverse Polarization Phenomena" - Ferrara, 28 to 31 May 2008 (http://www.fe.infn.it/transversity2008/)
Transversity and transverse spin of the proton are among the most important topics in the field of hadronic physics. The workshop was organized within the project PRIN 2006 and followd the one organized in Como in 2005. The workshop brought together both theoretical and experimental physicists involved in the study of the transverse structure of the nucleon, to exchange ideas and updates on the latest experimental data on the subject. As chair Paolo Lenisa was responsible for both the organization of the scientific program and for the logistics of the workshop which was attended by eighty physicists from around the world. The use of funds from the Virtual Institute for QCD VI-QCD, of which Paolo Lenisa is local manager, was used to finance the participation to the Workshop of nearly a dozen Italian and foreign students.
P. Lenisa is co-editor of the Proceedings of the Workshop (G. Ciullo, M. Contalbrigo, D. Hasch and P. Lenisa: Proceedings of "Transversity 2008 - 2nd Workshop on Transverse Polarization Phenomena" World Scientific - 2009)
- Chairman of the Workshop: PST2009 - XIII International Workshop on Polarized Sources, Targets and Polarimetry - Ferrara, 07 - 11 September 2009 (http://web.fe.infn.it/PST2009/)
Paolo Lenisa organized as Chairman the Workshop PST2009 - XIII International Workshop on Polarized Sources, Targets and Polarimetry held in Ferrara from 7 to 11 September 2009. The International Workshop organized on a biennial basis, aims at gathering together world experts in the technology of polarized beams and targets and related polarimetry. The nomination and subsequent selection of Ferrara as the seat by the International Spin Physics Committee, is an international acknowledgment for the expertise gained in the polarization field by Paolo Lenisa and his group. The workshop served to provide a complete overview of the different types of targets and polarized beams adopted in hadronic physics, but also properly highlighting the potential applications in fields outside physics, as in medicine. Particular attention in the organization of the scientific program was the discussion time, with the aim of promoting the exchange of information between the various experiences. The use of funds of the Virtual Institute QCD (VI-QCD) of which Paolo Lenisa was responsible, allowed to contribute to the travel expenses of more than a dozen students. Overall, the workshop was attended by over eighty physicists from around the world. As Chairman. P. Lenisa was occupied by both the organization of the scientific program and the logistics.
Paolo Lenisa is Co-editor of the Proceedings of the Workshop, published by World Scientific (G. Ciullo, M. and P. Contalbrigo Lenisa Proceedings of PST2009 - XIII International Workshop on Polarized Sources, Targets and Polarimetry, "- World Scientific 2011)
- Co-organizer of the Workshop "STORI11, 8th International Conference on Nuclear Physics at Storage Rings", Frascati, Italy, 9-14 October 2011 (http://www.lnf.infn.it/conference/stori11/)
Paolo Lenisa was part of the organizing committee of STORI11, held in Frascati 9 to 14 October 2011. The purpose of the conference, organized every three years, is to provide a broad overview of various aspects of nuclear physics studied in storage rings. Paolo Lenisa was conviener of the session devoted to experiments and future facilities and is co-editor of the Proceedings of the Conference published electronically by Proceedings of Science (PoS).
- Co-chair of the International School Niccolo’ Cabeo – 2013: “Physics beyond the Standard Model: the Precision Frontier”, Ferrara, Italia, 20-24 may 2013 (http://www.fe.infn.it/cabeo_school/)
Paolo Lenisa is Co-chair of the International School Niccolo’ Cabeo – 2013: “Physics beyond the Standard Model: the Precision Frontier”, held in Ferrara, Italia, 20-24 may 2013.
It is nowdays well established that the Standard Model is not the ultimate theory of the basic consitutents of our universe and their interactions. The challenge of the present and future fundamental research is to investigate the limits of the Standard Model and establish the experimental basis for a new and more complete theory.
Complementary to the global and highly localized effort of high-energy exploration at CERN, a plethora of worldwide-spread small and middle scale experiments are exploiting precision measurements to seek for sign of physics not included in the Standard Model.
The School addresses graduate students and young researchers and is meant to offer an overview of these experimental searches in the theoretical framework of present effective field theories. Program includes introductory lectures to quantum field theory and supersimmetry and dedicated experimental presentations on flavour physics and the search for EDM, antimatter, antigravity, dark-forces, gravitational waves.
PART IV: TEACHING ACTIVITY
Paolo Lenisa teaches the courses of General Physics I and II, recently joined in General Physics, for Faculty of Engineering, University of Ferrara since 2000. The courses are framed in the first year of the Degree in Engineering, and concern an average of 150 students per year. In the current structure, the course of General Physics is carried out in a period of three months and covers the topics of vector calculus, single particle dynamics, dynamics and statics of the rigid body and thermodynamics. The course consists of a total of 120 hours of front-lectures corresponding to 12 credits.
Particular importance for the management of courses, in compatible way with his research activity, has covered the intensive mode of carrying them out, which allows the compaction in periods of two/three months. Also the adoption of partial tests dedicated to the various topics covered in the course played also an important role in this sense, besides being highly appreciated by the students.
The popularity of the teaching of Paolo Lenisa by students is reflected by the evaluation questionnaires of the students who put his Course of General Physics as the most popular of the entire degree course in the last two academic years (questionnaires are publicly available from the website University of Ferrara).
To manage the contact with the students in an appropriate manner even during periods of absence from the office, great importance has played the introduction of a website dedicated to the course, which in the course of the last year came to a total of approximately 100,000 contacts in 10 years ( http://www.fe.infn.it/ lenisa ~ /). The website collects some applets to supplement the course topics and exercises done in class.
In parallel to the teaching activities related to the described courses, Paolo Lenisa carried out supervision and mentoring for thesis and PhD in supporting activities carried out within the research of HERMES Collaboration before, and PAX later. In particular Paolo Lenisa has been supervisor of doctoral thesis 5 and 8 thesis in physics at the University of Ferrara.
CHRONOLOGY
- Academic Year 1998 - 1999
Exercises performed in the course in General Physics II Degree in Civil Engineering, Faculty of Engineering, University of Ferrara.
Tutor of the Diploma thesis in Physics for the student David Reggiani, Faculty of Sciences, University of Ferrara entitled: "Study and Application of a Transversely Polarized Target for the HERMES experiment at HERA"
- Academic Year 1999 - 2000
Course of General Physics II Degree in Civil Engineering, Faculty of Engineering, University of Ferrara
Tutor of the Diploma thesis in Physics for the student Severino Tessarin, Faculty of Sciences, University of Ferrara, entitled "Determination of the accuracy of the measurement bias for the target experiment HERMES"
- Academic Year 2000 - 2001
Course of General Physics II Degree in Civil Engineering, Faculty of Engineering, University of Ferrara.
- Academic Year 2001 – 2002
Course of General Physics I Degree in Civil Engineering, Faculty of Engineering, University of Ferrara.
- Academic Year 2002 - 2003
Course of General Physics I Degree in Civil Engineering, Faculty of Engineering, University of Ferrara.
Supervisor for PhD in Physics at University of Ferrara for the student D. Reggiani. Title of the thesis "Precision Measurement of the Polarization of the HERMES Target"
- Academic Year 2003 - 2004
Course of General Physics I Degree in Civil Engineering, Faculty of Engineering, University of Ferrara.
- Academic Year 2004 - 2005
Course of General Physics I Degree in Civil Engineering, Faculty of Engineering, University of Ferrara.
Series of two lectures given at XV Study Days on Detectors, Turin Villa Gualino, 1:02:05 to 4:02:05 entitled "Polarization Rings Collection."
- Academic Year 2005 - 2006
Course of General Physics I Degree in Civil Engineering, Faculty of Engineering, University of Ferrara.
Supervisor for thesis PhD in Physics for the University of Ferrara student M. Capiluppi. Thesis title: "First Measurement of the Spin-Exchange Collisions Cross Section in the Low Temperature Region"
- Academic Year 2006 - 2007
Course of General Physics I Degree in Civil Engineering, Faculty of Engineering, University of Ferrara.
- Academic Year 2007 - 2008
Course of General Physics I Degree in Civil Engineering, Faculty of Engineering, University of Ferrara.
Course of General Physics II Degree in Civil Engineering, Faculty of Engineering, University of Ferrara.
Tutor for Master thesis in Physics at the University of Ferrara for the student P. Benati. Thesis title: "Characterization of a new trigger board for spin-filtering experiments"
Tutor for Master thesis in Physics Thesis at the University of Ferrara for the student S. Bertelli. Thesis title: "Study of the rdeuteron-breakup reaction in spin-filtering experiments for the polarization of antiproton beams"
- Academic Year 2008 - 2009
Course of General Physics I Degree in Civil Engineering, Faculty of Engineering, University of Ferrara.
Course of General Physics II Degree in Civil Engineering, Faculty of Engineering, University of Ferrara.
- Supervisor of the doctoral thesis in physics at the University of Ferrara for the student L. Barion. Thesis title: "Internal polarized gas targets: systematic studies on intensity and correlated effects."
- Tutor for Master thesis in Physics at the University of Ferrara for the student G. Guidoboni. Thesis title: "Design of the interlock-system of a test bench for silicon detectors"
- Academic Year 2009 - 2010
Course of General Physics Degree in Civil Engineering, Faculty of Engineering, University of Ferrara.
Tutor for the Master thesis in Physics at the University of Ferrara for the student A. Lupato. Thesis title: "Development of atomic beam sources of hydrogen and deuterium gas at high intensity."
- Academic Year 2010 - 2011
Course of General Physics Degree in Civil Engineering, Faculty of Engineering, University of Ferrara.
- Academic Year 2011 - 2012
Course of General Physics Degree in Civil Engineering, Faculty of Engineering, University of Ferrara.
Tutor of the PhD thesis in Physics at the University of Ferrara for the student P. Benati. Thesis title: "Development of a new trigger system for spin-filtering studies".
Tutor for the PhD thesis in Physics at the University of Ferrara for student S. Bertelli. Thesis title: "Proton induced deuteron breakup reactions at COSY."
Tutor for the master thesis in Physics at the University of Ferrara's Student E. Dall'Occo. Title of the thesis:
Optical characterization of radiators for aerogel Cherenkov detectors"
Tutor for the master thesis in Physics at the University of Ferrara student A. Ferroni. Title of the thesis:
"Density measurement of a polarized target for the PAX-experiment"
PART V: PRESENTATIONS AT CONFERENCES, MEETINGS, SCHOOLS
1996
- VII International Conference on Accelerators Applications in Industry and Research,
Nov. 1996, Danton (Texas)
"New Techniques for Laser Cooling of an Ion Beam in a Storage Ring"
1997
- 3rd Euroconference on Atomphysic heavily charged with stored ions
Sept. 1997, Ferrara (Italy)
"White-light Laser Cooling at the TSR"
- 14th International Spin Physics Symposium (SPIN 2000)
Oct 16-21, 2000, Osaka (Japan)
"The HERMES Internal Polarized Hydrogen and Deuterium Target"
2001
- Deutsche Gesellschaft Physikalische Spring Meeting
March 19 to 23, 2001, Erlangen (Germany)
"Das HERMES Polariziertes HD Target" (in German)
- International Workshop on Polarized Sources and Targets (PST 01)
Sep 30 - Oct 4, 2001, Nashville - Indiana (USA)
"The Gaseous Polarized HD Target of the HERMES Experiment"
2002
- Summer School and Workshop on COSY Physics
Aug. 28 - Sept. 4, 2002, Jülich (Germany)
"Study of Heavy Meson Production with a Polarized Internal Gas Target at COSY"
- 15th International Spin Physics Symposium (SPIN02)
Sep 9-14, 2002, Brookhaven National Lab - NY (USA)
"New Precision Results on the Spin Structure Function G1D"
- 15th International Spin Physics Symposium (SPIN02)
Sep 9-14, 2002, Brookhaven National Lab - NY (USA)
"Nuclear Polarization of Hydrogen Atoms on recombined Drifilm"
2003
- Quarks in Hadrons and Nuclei II
Sep 15 - 20, 2003, Rothenfels Castle, Oberwoelz, (Austria)
"Transversity Measurements at HERMES"
- 10th International Workshop on Polarised Sources and Targets
Sep 22-26, 2003, Novosibirsk (Russian Federation)
"The HERMES transversely Polarized Hydrogen Target"
2004
- "Scientific Opportunities and Challenges - China and the International Facility at Darmstadt"
April 14-16, Beijng (China)
"PAX: Polarized Antiproton eXperiments"
- 1st Caucasian_German School and Workshop on Hadron Physics
Aug. 30-Sept. 4 2004, Tbilisi (Georgia)
"PAX (Polarized antiprotons eXperiments)"
- 16th International Spin Physics Symposium (SPIN04)
Oct 10 - 16, 2004, Trieste (Italy)
"The HERMES Polarized Hydrogen and Deuterium Gas Targets"
2005
- XV Study Days on the detectors,
February 1 to 4, 2005, Villa Gualino - Torino (Italy)
"Polarization Rings Collection."
- 13th International Workshop on Deep Inelastic Scattering and QCD (DIS 2005)
April 27 - May 1, 2005, Madison-Wisconsin (USA)
"Spin Physics with Polarized antiprotons at GSI"
- Partonic structure of hadrons (concepts and phenomenology)
May 9-14, 2005, Trento (Italy)
"Polarized Antiproton Experiments at GSI"
- 6th International Conference on Nuclear Physics at Storage Rings
23-26 May 2005, Bonn (Germany)
Presentation by invitation.
"The PAX Proposal: Physics with Polarized antiprotons at GSI"
- HiF05 - High Intensity Frontier Workshop
Presentation by invitation.
May 28 - Jun. 01, 2005, Elba Island (Italy)
"Physics with Polarized antiprotons"
- Hpc2005 - Workshop on Hadronic Physics at COSY
July 25-29, 2005, Bad Honnef (Germany)
"Proton Spin and Polarized antiprotons"
- XCI National Congress of the Italian Society of Physics
Sept. 26 - Oct. 1, 2005, Catania
Presentation by invitation:
"Physics with Polarized Antiprotons"
2006
- 14th International Workshop on Deep Inelastic Scattering and QCD (DIS 2006)
April 20 to 24, 2006 Tsukuba, Japan
"Polarized measurements at sea JPARC."
- Observables in Antiproton-Proton Interactions and Their relevance in QCD
July 3-8, 2006, Trento, Italy
"The PAX Project"
- 2nd Caucasian_German School and Workshop on Hadron Physics
Aug. 31-Sept. 8 2006, Tbilisi (Georgia)
Presentation by invitation:
"Spin-filtering experiments"
2007
- Workshop: "Hard QCD with antiprotons at GSI-FAIR"
July 16-28, 2007, Trento, Italy
Presentation by invitation:
"Polarization technology at FAIR."
- Workshop: "Polarized antiprotons: how?"
August 29-31, 2007, Daresbury (Liverpool), UK
Presentation by invitation:
"Spin-Polarized antiprotons and physics."
- 11th International Conference on Meson-Nucleon Physics and the Structure of the Nucleon (MENU 2007)
September, 10-14, 2007 FZJ-Jülich, Germany
Presentation by invitation:
"Toward polarized antiprotons at FAIR."
2008
- Workshop: "Nuclear Medium Effects on Quarks and Gluon Structure of Hadrons"
July 03-07, 2008, Trento, Italy
Presentation at the invitation
"FAIR and PAX."
2010
- Workshop on High-energy hadron physics with hadron beams
January 06-08, 2010, Tsukuba, Japan
Presentation by invitation:
"Structure Functions and Spin-physics at FAIR"
- Workshop on Studying the hadron structure in Drell-Yan reactions
April 26-27, 2010, CERN, Switzerland
Presentation by invitation:
"Future Drell-Yan experiments at FAIR"
- SPIN2010 - 19th International Spin Physics Symposium
September 27th - October 2nd 2010, Juelich, Germany
Presentation at the invitation
"Highlights of PST2009 Workshop on Polarized Sources, Targets and Polarimetry"
2011
- The Structure and Dynamics of Hadrons-XXXIX International Workshop on Gross Properties of Nuclei and Nuclear Excitations
Jaunuary 16th-22nd, 2011, Hirschegg, Kleinwalsertal, Austria
Presentation by invitation:
"Possible future experiments on Hadron Structure at FAIR"
- LEAP 2011 - 10th International Conference on Low Energy Antiproton Physics
April 27th - May 1st, 2011, Vancouver, Canada
Presentation by invitation:
"Perspectives for Polarized antiprotons"
- PSTP 2011 - XIV International Workshop on Polarized Sources, Targets and Polarimetry
September, 12th-16th St. Petersburg, Russia
Presentation by invitation:
"The road to Polarized antiprotons"
2012
- Spin-physics Workshop in Gatchina
June, 24th-27th, Gatchina, Russia
Presentation by invitation:
"Perspectives for Polarized antiprotons."
- 5th Georgian-German School and Workshop in Basic Science
August, 5th-11th, Tbilisi, Georgia
Presentation by invitation:
"Polarized antiprotons: why and how."
Born in Udine on 06/17/65
Studies
- 1992 Degree in Nuclear Engineering from Politecnico di Milano with 100/100 cum laude.
- 1997 PhD in Physics at the University of Ferrara with “excellent” judgment.
Professional Positions
- 1997 - 1999 Guest scientist at the Max-Planck Institute in Heidelberg.
- 1999 - 2014 Researcher at the University of Ferrara
- 2014 - 2017 Associate Professor in Experimental Physics at the University of Ferrara
- 2017 - Professor in Nuclear and Subnuclear Physics at the University of Ferrara
CONTENTS:
• PART 0: SUMMARY
• PART I: SCIENTIFIC ACTIVITY
• PART ll: ADMINISTRATIVE AND MANAGEMENT ACTIVITY
• PART III: ORGANIZATIONALY ACTIVITY
• PART IV: TEACHING ACTIVITY
• PART V: LIST OF PRESENTATIONS AT CONFERENCES, MEETINGS, SCHOOLS
SUMMARY
Scientific Activities
Main current:
- Development and management of polarized targets.
- Production and application of polarized beams of antiprotons.
- Applications of the technology of polarization to hadronic physics: study of the structure of the nucleon.
- Study of the form factors of the proton.
- Applications of the technology of polarization on the fundamental physics: measurement of the electric dipole moment of the proton and deuteron, Time Reversal Invariance
- Polarized fusion
Main previous activities:
- Design and development of photocathodes with negative electron affinity.
- Laser cooling of ions in storage rings.
Main scientific results
- First demonstration of the application of an innovative wide band laser to laser cooling of an ion beam in a storage ring.
- First measurements of the spin-exchange collisions cross section at low temperature.
- First direct measurement of the helicity of the valence quarks and quark s.
- First experimental evidence of the transversity and of a non-zero angular momentum of the quarks in the proton (Collins and Sivers effects).
- Demonstration of non-applicability of the mechanism of spin-flip to the polarization of a beam stored in a storage ring.
- Demonstration of the polarizability of beam stored in a storage ring by spin-filtering.
Main national and international scientific responsibilities
- 2000 – 2005 Coordinator of the management group of the polarized target experiment HERMES (DESY-HH).
- since 2004 Co-spokesperson of the International Cooperation PAX
2005 Proponent as co-spokesperson of the PAX experiment at the new facility FAIR in Darmstadt, Germany.
- 2007-2008 Ideation preparation and management as Spokesperson of a measure of depolarization of a beam of protons at the ring COSY to FZJ-Jülich
- 2008 Co-proponent and team leader for Ferrara of OLYMPUS experiment at DESY in Hamburg for the measurement of two-photon contribution to the form factors of the proton.
- 2009 proponent acting Spokesperson of the measurement of the spin-dependence of the cross section at the ring proton antiproton AD CERN.
- 2008-2011 Planning, preparation and management as Spokesperson of a measure of spin filtering at the COSY ring.
- 2011 proponent acting Spokesperson of a measure of the coherence time of spin-longitudinal at the ring COSY.
- 2012 Co-proponent collaboration and co-responsible for the PAX experiment TRIC for a test of invariance at the COSY ring of the FZ-Jülich
- 2012 Co-proponent and responsible for the group of Ferrara experiment JEDI for the measurement of the electric dipole moment of the proton and deuteron at the ring COSY of the FZ-Jülich
Main administrative and managing national and international responsibilities.
- 2003 - 2005 Responsible for the research unit of Ferrara for PRIN 2003 project approved and funded by MIUR: "Study of SIDIS reactions ep -> e'hX for the analysis of transversality of the nucleon."
- since 2005 National responsible of the PAX experiment at the Group III-INFN
- 2006 - 2008 Responsible for the research unit of Ferrara for PRIN 2006 project approved and funded by MIUR: "Study of transverse spin in the nucleon through semi-inclusive DIS reactions ep -> e'hX, Drell-Yan processes pbar p -> l + l-and pbar p elastic scattering. "
- 2007-2010 Scientific Officer for the University of Ferrara of the Virtual Institute of European institutions funded by the Helmholtz-Gesellschaft: "Virtual Institute on Spin and Strong QCD".
- 2008-2011 Scientific responsible for the unit of Ferrara of the Joint Research Activity "Hard-Exclusive Reactions (Hardex)", Work Package 23 of the project "Hadron Physics 2" (I3HP2) funded by the European Commission within the VII Framework Programme.
- 2008-2011 Scientific responsible for the unit of Ferrara of the Joint Research Activity "Polarized antiprotons (PolAntiP)", Work Package 25 of the project "Hadron Physics 2" (I3HP2) funded by the European Union under the Seventh Framework Programme (Grant Agreement 227431).
- 2009 -2012 Responsible for the Research Unit of Ferrara PRIN for 2008 project approved and funded by MIUR: "Study of transverse spin in the nucleon through semi-inclusive DIS reactions ep -> e'hX, Drell-Yan processes p pbar -> l + l-and pbar p elastic scattering. "
- 2009-2013 Scientific coordinator of the collaborative project between the University of Ferrara and the Forschungszentrum - Jülich entitled "Spin-filtering studies in Storage Rings" for the financing of joint doctoral and post-doctoral students. Contract No. 41853505 (FAIR-009).
- 2010-2015 Scientific responsible for the unit of Ferrara Advanced Research Grant "POLPBAR" financed by the European Council resarch within the VII Framework Programme (Grant Agreement no. 246980).
- since 2011 member of the International Spin Physics Committee
- 2012 - 2014 Scientific responsible for the unit of Ferrara of the Joint Research Activity "Polarized antiprotons (PolAntiP)", Work Package 25-part of the Project "Hadron Physics 3" (I3HP3) funded by the European Union under the Seventh Framework Programme .
- since 2012 Coordinator of the Section of Ferrara in the National Scientific Committee III INFN
- 2013-2014 Scientific coordinator of the collaborative project between the University of Ferrara in collaboration between the Forschungszentrum - Juelich entitled "Spin-tracking studies in Storage Rings" for the financing of joint doctoral and post-doctoral students. Contract No. 42028694 (FAIR-021).
Conducts Referee for the following journals:
- Nuclear Instruments and Methods
- Europhysics Journal.
- Radiochemical Acta
Since 2005 is member of the Teaching Committee for PhD in Physics from the University of Ferrara.
Main organizational responsibilities
- 2005 Co-organizer of the International Workshop on "Transverse Polarization Phenomena in Hard Processes" (Como, 7-10 September 2005)
- 2006 Co-organizer of the second "Caucasian-German School and Workshop on Hadron Physics" (Tbilisi, Georgia, 4-8 September 2006)
- 2007 Co-organizer of the Workshop "ANKE / PAX Workshop on Spin-Physics," Ferrara May 29-June 1, 2007
- 2007 Co-organizer of the workshop "Hard QCD with antiprotons at GS-FAIR", ECT, Trento, Italy, 16-20 July 2007
- 2008 Chairman of the Workshop "Transversity 2008 - 2nd Workshop on Transverse Polarization Phenomena" Ferrara, 28-31 May 2008
- 2008 Co-chairman of the Workshop "Polarized antiprotons" Bad-Honnef (Germany) 24-26 June 2008
- 2009 Chairman of the Workshop: PST2009 - XIII International Workshop on Polarized Sources, Targets and Polarimetry, Ferrara, Italy, 07-11 September 2009
- 2011 Co-organizer of the Workshop "STORI11, 8th International Conference on Nuclear Physics at Storage Rings", Frascati, Italy, 9-14 October 2011
- 2013 Co-chair of the International School of doctorate "Niccolo’ Cabeo": "Physics beyond the standard model: the precision frontier", Ferrara, Italy, 20-24 May 2013
Teaching activity
- 1999 to 2000 General Physics II Course for the Master of Science in Civil Engineering
- 2001 Course of General Physics I for the Degree in Civil Engineering
- 2005 Cycle of lectures to the XV Study Days on the detectors at Villa Gualino (TO), (Course for graduate students) entitled "Polarization in storage rings"
- 2002 to 2008 General Physics I Course for the Master of Science in Civil Engineering
- 2007 to 2008 General Physics II Course for the Master of Science in Civil Engineering
from the 2009 Course of General Physics for Civil Engineering
Supervisor of 5 PhD in Physics
Supervisor of 8 thesis in Physics
Scientific publications
- Author of over 150 articles, more than 100 of which on international journals with referee.
- Signatory of 11 proposals for experiments and letters of intent including 7 as Spokesperson.
- Curator of the Proceedings of the 4th International Conference.
Public presentations
- He has presented at 33 conferences and congresses (32 international) of which 14 by invitation.
Dissemination activities
- Since 2012 is part of the editorial staff of the website of scientific INFN "Science for all"
Other information
- Fluency in written and spoken English.
- Fluency in written and spoken German.
- Basic knowledge of the Russian language.
PART I: SCIENTIFIC ACTIVITY
Brief summary and guidelines.
Paolo Lenisa was trained as atomic physicist, contributing as a graduate student a graduate student first and later as a guest scientist at the Max-Planck-Institute in Heidelberg, to the study of an innovative laser source for the cooling of a stored ion beam in storage rings. Among the experimental results, it is worthwhile of mention the first experimental evidence, obtained at the ring TSR of Heidelberg, of the effectiveness of the use of an innovative broad-band laser in the cooling of a beam of ions [PRL 80 (1998) 2129]. The result proves unambiguously that such type of source is able to counter the intrabeam-scattering phenomenon representing the dominant mechanism of heating of the longitudintal phase space of the stored particles.
Paolo Lenisa was the winner of the competition as a researcher at the University of Ferrara in 1998. His training as a atom-physicist and experience on storage rings allowed him to fit naturally in the management group of the polarized internal target experiment HERMES (DESY-Hamburg) in which he played the role of coordinator from 2000 to 2005. HERMES, which concluded its data-taking in 2007, and was a Depp-Inelastic Scattering experiment, which used internal gaseous hydrogen and deuterium targets, longitudinally and transversely polarized hydrogen, positioned on the electron/positron beam in the HERA storage-ring at DESY-Hamburg (Germany). Under the direction of Paolo Lenisa, the target has stabilized its performance allowing the group to publish 10 articles on international journals [NIMA 482 (2002) 606, EPJD 18 (2002) 37, NIMA 508 (2003) 268, NIMA 482 (2002) 1, NIMA 505 (2003) 633, NIMA 496 (2003) 277, NIMA 496 (2003) 263, EPJD 29 (2004) 21, NIMA 540 (2005) 68, EPJD 48 (2008) 343]. Among these, mention has to be deserved to a couple of measurements related to atomic physics that were stimulated and developed thanks to the expertise of Paolo Lenisa: the first measure of remnant polarization of molecules obtained by recombination of an inert surface [EPJD 29 (2004) 21] and the first measurement of the spin-exchange collision cross section between hydrogen atoms at low temperature [EPJD 48 (2008) 343].
The excellent performance of the target, allowed the HERMES to play a key role in the international community in the study of the spin structure of the proton and deuteron. In particular, the analysis of the semi-inclusive asymmetries collected in 1996-2000 with longitudinally polarized hydrogen and deuterium, has enabled the HERMES Collaboration to measure for the first time in a direct way the longitudinal polarization of the valence quarks u and d and s quark the sea [PRL 92 (2004) 012005, PRD 71 (2005) 012003]. Confirming the indications of the indirect inclusive measurements, the polarization of the u-quark was positive with greater polarization in large x where the quark valence dominate, while the polarization of the d-quark is negative. The measurements also show that the polarization of the sea quarks is small. Taken together, all these measures, stimulated by the so-called "spin crisis" of the late '80s, show conclusively that the spin of the quarks generates less than half the spin of the proton and that the only contribution comes from those of quarks value.
The following data taking with transversely polarized hydrogen target (2002-2005), has allowed HERMES to play a pioneering role in the study of spin and transverse momentum distributions in the nucleon. This study is crucial for understanding the structure of the proton and its importance is underscored by the funding of three dedicated research PRIN projects by MIUR (Italian Ministery of University and Research), of which Paolo Lenisa is responsible for the research unit of Ferrara (PRIN 2003, PRIN 2006 , PRIN 2008). The funding made it possible to support the members of the group in the data analysis of HERMES. We mention in particular the extraction of Sivers and Collins amplitudes, both measured with unpolarized beam and transversely polarized hydrogen target [PRL 94 (2005) 012002, PRL 103 (2009) 152002, PLB 693 ( 2010) 11]. These two azimuthal amplitudes contain information on fundamental parton distribution functions of which little was known before. The first, called Sivers function, describes the correlation between the transverse momentum of the quarks and the transverse polarization of the nucleon. The second, called transversity, is related to the number density of transversely polarized quarks within a transversely polarized nucleon. HERMES has provided the first experimental evidence that both transversity and the Collins fragmentation functions are not null. It also provided the first experimental evidence that the Sivers function itself is non-zero, implying the existence of a non-zero orbital angular momentum of quarks in the nucleon, hitherto never measured. The azimuthal asymmetries detected by HERMES combined with those of the COMPASS at CERN and the measurement of the Collins function at BELLE (KEK, Japan) made it possible to carry out the first extraction of the transversity distribution of the nucleon, a result that represents a milestone for hadron physics. At the same time, the measurements of the Sivers’ amplitudes, has been recently allowed the extraction of the Sivers function for the u and d quarks u and d, obtaining, for the two flavors, values approximately equal in absolute value and opposite in sign. This result, in agreement with predictions can be phenomenologically interpreted as evidence of the fact that, inside the proton, u and d quarks have orbital angular momentum of opposite sign.
The acknowledgement in the international community for his expertise in the technology of polarization in storage rings and interest in the study of the structure of the nucleon, have allowed Paolo Lenisa to promote as Co-Spokesperson, the International Collaboration PAX (Polarized Antiproton eXperiments) and to submit in 2005 a Technical proposal to the FAIR facility at GSI in Darmstadt [http://www2.fz-juelich.de/ikp/pax/portal/documents/proposals/files/techproposal20060125.pdf]. This proposal is linked to possible experimentation with the first ever antiproton beam intense polarized.
To support the proposal, Paolo Lenisa has in recent years studied the mechanism of polarization of a nucleon beam of nucleons circulating in a ring, both from the theoretical and the experimental points of view [94 PRL (2005 ) 014 801, PLB 674 (2009) 269, PLB 718 (2012) 64, http://www2.fz-juelich.de/ikp/pax/portal/documents/proposals/files/proposal20071020.pdf, http://www2.fz-juelich.de/ ikp/pax/portal/documents/proposals/files/proposal20080414.pdf, http://www2.fz-juelich.de/ikp/pax/portal/documents/proposals/files/proposal20090426.pdf]. Despite the many existing proposals, before the experimental activity promoted by Paolo Lenisa, only one experimental evidence existed related to a spin-filtering test of protons, carried out at the ring TSR in Heidelberg in 1992.
In principle, there are two possibilities to polarize a beam of particles of spin ½, as antiprotons, stored in a storage ring. The first, called "spin-flip", is based on the existence of a mechanism that gives rise to a different transition probabilities between up and down states with respect to the opposite process. The second, called "spin-filtering", involves the use of a process that selectively removes one state over the other from the ring. Paolo Lenisa has promoted, implemented and carried-out a series of measurements devoted to the understanding the mentioned mechanisms. A first measurement has allowed to provide the experimental demonstration of the ineffectiveness of the technique of spin-flip [PLB 674 (2009) 269], leaving spin-filtering as the only perspective for the “in-situ” polarization of a stored beam of antiprotons. A second measurement has proven the effectiveness of the filtering mechanism in spin to polarize a beam stored in a storage ring. The measurement is of fundamental importance for the field of research. It has in fact confirmed the recent theoretical understanding of the mechanism of polarization filtering, subject of controversial theoretical interpretations in the past. It has also allowed (as proof of the perfect control of all the experimental systematic effects) the extraction of the proton-proton polarizing cross-section [PLB 718 (2012) 64]. As acknowledgment of the importance the research, the European Union has funded the mentioned studies by an Advanced Research Grant (POLPBAR: 2010-2015), of which Paolo Lenisa is scientific responsible for the University of Ferrara and two Joint-Research Activities in the Projects Hadron Physics 2 (2008-2011) and Hadron Physics 3 (2012-2014) of which Paolo Lenisa is scientific responsible for the INFN of Ferrara.
In order to study the applicability of the spin-filtering technique to the polarization of antiprotons, the PAX Collaboration, led by Paolo Lenisa, has developed and submitted in 2009 a Technical Proposal to the CERN-SPS Committee devoted to the measurement of the spin dependence of the proton-antiproton cross-section [http://www2.fz-juelich.de/ikp/pax/portal/documents/proposals/files/proposal20090426.pdf]. The precise knowledge of this cross section is necessary for the design of a dedicated polarizer storage ring. The existing theoretical predictions for this cross section, reflect the uncertainty of the description of the annihilation proton-antiproton process and disagree by almost a factor of 2, making and experimental measurement indispensable. The AD ring at CERN is the only machine in the world capable of storing antiprotons in an energy range favorable to spin filtering (between 50 and 500 MeV).
Giving continuity to the expertise gained in the technology of polarization in storage rings, Paolo Lenisa has recently oriented his interest in applications related to fundamental physics measurements. In this framework, have to be inserted a test of time invariance at the COSY ring and the measurement of the electric dipole moment (EDM) of proton and deuteron in a storage ring of new generation. These measurement of interest for the exploration of physics beyond the Standard Modal, represent an important application for the knowledge in polarization technology, unique in Italy, acquired over the years by Paolo Lenisa, and his research group. In this regard, Paul Lenisa, has submitted proposals for dedicated experiments to the Physics Advisory Committee of COSY [http://www2.fz-juelich.de/ikp/publications/PAC40/176.6-Ed-sum.pdf, http:// www2.fz-juelich.de/ikp/publications/PAC40/EDM-COSY-Proposal_cover_23.04.2012.pdf, http://www2.fz-juelich.de/ikp/publications/PAC40/215-TRI_Prop_sum.pdf], as responsible of the Ferrara group, one of which as Spokesperson. For further details, please refer to the detailed description of the activity.
We finally mention a recent activity in which Paolo Lenisa is involving his group, which is also related to the technology of polarized targets. Paolo Lenisa is promoter of a scientific collaboration agreement between INFN Ferrara, the Nuclear Physics Institute - PNPI (Gatchina, Russia) and the FZJ (Jülich, Germany) for the study of fusion reactions of light elements with polarized initial particles. The project aims at measuring the cross section and angular distribution of the products of the nuclear fusion reactions D + D and D +3 He in the energy range 10-100KeV. This measure, besides presenting physical interest in itself, is linked to the possibility of using polarized deuterons as a fuel for thermonuclear fusion plants. The contribution of the group of Ferrara is related t the atomic polarized source. It is expected to move a polarized atomic source, presently in Ferrara, to the Laboratory of Gatchina by the end of 2012. After a period of adaptation of the source and commissioning of the entire experimental setup, the beginning of the data taking is expected in 2014.
PERSONAL CONTRIBUTIONS AND CHRONOLOGY
- Development of innovative cooling techniques with a laser beam (1994-1998)
The research carried out as part of the doctoral thesis has been the development of new cooling and diagnostics techniques of stored ions by means of laser beams. Laser cooling is the most effective method of cooling of an ion beam in the longitudinal phase and makes use of the radiation pressure generated by a laser beam resonant with a closed transition between two energy levels of the stored ions. Paolo Lenisa was proponent of an innovative method of laser cooling able to improve the cooling efficiency. The greatest obstacle to the longitudinal laser cooling of ions in a storage ring is the phenomenon of internal collisions (intrabeam-scattering). The coulomb binary collisions between the particles of the beam are able to transfer part of the kinetic energy of the transverse degrees, which are not affected by the laser cooling, in the longitudinal one, bringing the ions outside the velocity capture range of the spontaneous force and making them effectively lost for the cooling cycle. The proposed idea is to use a so-called "white laser", i.e. a laser with a large spectral width, compensating for the Doppler shift and enabling ions with different velocities to be simultaneously resonant with the radiation. Paolo Lenisa has collaborated to the development of the first ever laser with broad spectrum (500 MHz) completely controllable in intensity and frequency. A test of the developed source and proposed technique has been successfully performed at the storage ring TSR of Heidelberg and has demonstrated the effectiveness of the technique to counteract the effect of Coulomb collisions between particles. The exposed arguments have been the subject of the doctoral thesis discussed at the University La Sapienza of Rome, with unanimous opinion of the Commission "excellent", on 7/17/97 with the: "Development of new cooling techniques and diagnostic laser to a beam of ions stored in a storage ring".
From 04.97 to 08.98 Paolo Lenisa was guest-scientist at the Max-Planck Institut fuer Kernphysik in Heidelberg, where he continued the testing activities of techniques for cooling of ions in a storage ring.
- Coordinator of the polarized target HERMES experiment at DESY in Hamburg (2000-2005).
The HERMES experiment (HERa Measurement of Spin), mainly devoted to the study of spin structure of the proton, has been in operation on the storage ring HERA at DESY in Hamburg from 1995 to 2007. The HERMES spectrometer detects the events generated by deeply inelastic scattering of polarized electron or positron at an energy of 27.5 GeV polarized off a polarized internal target. Besides identifying inclusive events, the HERMES spectrometer is provided with a RICH detector, with a double radiator able to distinguish pions, kaons and protons and a spectrometer capable of detecting up to 14 charged tracks fillers, allowing semi-inclusive and exclusive analysis.
From 1996 to 2005 HERMES employed an internal polarized hydrogen/deuterium target. The orientation of target spin has been assured by the application of an external magnetic field, that had longitudinal direction up to 2000 and has been changed to traverse in 2001. The polarized target was dismantled in 2005 to host a large acceptance recoil detector. The target has been realized through a beam of polarized atoms that after being produced by a source atomic were injected into a storage cell which was an integral part of the vacuum tube of the ring itself; atoms diffusing towards the open ends of the cell, were then removed by an efficient pumping system. In order to limit the phenomena of recombination and depolarization due to collisions of atoms with the walls, the storage cell was coated with an inert polymeric material based on silicon (Drifilm) [NIMA 496 (2003) 277]. A sample of gas from the cell, diffusing through a second side tube, was analyzed by a quadrupole mass spectrometer to determine the atomic fraction and a Breit-Rabi polarimeter to measure the atomic polarization [NIMA 482 (2002), 606].
Paolo Lenisa has served as coordinator of the target group in the period 2000-2005. The management group of the target involved an international collaboration of physicists including besides the University of Ferrara, the University of Erlangen, Monaco and Madison, collaborators from MIT in Boston and the University of Novosibirsk.
In the long data taking period, the HEREMS target, only in high-energy physics to adopt this sensitive technology, has gone from being a craft to fully professional, as evidenced by the stability of the data collected and the reduction of systematic errors [see for example NIMA 540 (2005), 68]. Exactly with the purpose of documenting this technological progress, that a careful description of the different parts of the apparatus and the subject of physics involved in the operation of the target has been undertaken, work which led to the publication 10 articles on international journals [NIMA 482 (2002) 606, EPJD 18 (2002) 37, NIMA 508 (2003) 268, NIMA 482 (2002) 1, NIMA 505 (2003) 633, NIMA 496 (2003) 277, NIMA 496 (2003) 263, EPJD 29 (2004) 21, NIMA 540 (2005) 68, EPJD 48 (2008) 343].
An additional problem in the management of a target such as the HERMES one, involving a period of several years of data taking, was represented by the need to reconcile the requirements of the experiment with the ones of the operators who were Diploma and PhD students and needed arguments for the theses. For this reason, in parallel to the data taking of HERMES, a series of interesting atomic physics measurements have been performed and published, made possible by the systematic control and appropriate use of the ductility of the target. These works are briefly described below.
One of these is represented by the first measurement of the nuclear polarization of recombined hydrogen molecules on an inert surface, like the one represented by the Drifilm-coated storage cell. This measurement was performed using the double-spin asymmetry in the cross section of polarized electron- polarized proton collision (called A_1), in particular exploiting the independence of the interaction between elementary virtual photon and the quark in a proton belonging to an atom or a molecule. The originality of the approach comes from the use of a spectrometer of high energy physics for a delicate measurement of surface physics. The result was the topic of the PhD thesis of which Paolo Lenisa has been tutor and published in an international journal [EPJ D 29 (2004) 21]. The application of the measurement to the data collected with polarized Hydrogen, has allowed a reduction of the total systematic error of such data by almost 50%.
Another atomic physics measurement performed with the HERMES target, was the first measurement of the spin-exchange collisions cross section between hydrogen atoms at low temperature (50 K-100 K). The measurement, of interest in astrophysics, has been made possible thanks to the ductility of the target of HERMES that allows the injection into the cell and subsequently detection of any combination of hyperfine states of the hydrogen atom, and also offers the possibility to vary the temperature of the gas by varying the temperature of the cell. The execution of the measure required the complete control of the complex target systematics and was performed without affecting the ordinary data taking of the experiment. The results were the subject of the PhD thesis of which Paolo Lenisa was tutor and has been published in international journals [EPJ D 48 (2008) 343].
Finally it should be mentioned that the experience gained and the contacts with the American University of Madison and Argonne, allowed to transfer the complex and delicate production technique and coating of the cells from the laboratory of the University of Wisconsin-Madison to the mechanical workshop of the University and INFN of Ferrara, which took responsibility for the design and production of the storage cells accumulation both HERMES in the period 1998 to 2007, and for the present OLYMPUS experiment (see next paragraph).
In 2000-2005 data taking period the HERMES target has collected about 20 million polarized DIS events. Of these, the over 10 million events collected with longitudinally polarized deuterium are still the best existing sample from the point of view of statistical and systematic error on the polarization measurement. The 6 million events collected with a transversely polarized hydrogen target were the first sample of the kind ever.
- Selection of some experimental results HERMES experiment.
The production of the HERMES experiment covers a wide spectrum in the field of hadronic physics and spin in particular. In the following we present some results linked to data taken with the polarized target in which the group coordinated by Paolo Lenisa have given a substantial contribution from both the experimental point of view, as in the case of the management of the polarized target, or of the data-analysis, as for the case of transverse data.
- Deep inelastic scattering with longitudinally polarized target.
In the period 1996-1997, HERMES has collected about 3 million events of Deep Inelastic Scattering (DIS) with a longitudinally polarized hydrogen target. This statistic, has enabled to determine the structure function g_1p (x) of the proton with an accuracy comparable to that of the most precise existing measurement performed at SLAC by the experiments E143 and E155 [PRD 75 (2007) 012 007]. The results of HERMES extend to x-values lower than those of SLAC, in a region so far only covered by the SMC experiment and are in perfect agreement with those of the previous experiments. The function g_1p (x) has a positive sign and is maximum around values of x ~ 1/3 that characterize the region of the valence quarks. In association with the so-called u-quark dominance of the proton (consisting of two u-quarks and a single d-quark, weighed with the square of the charge in cross section), this result reflects the tendency of u-quark to be positively polarized (Delta u> 0), that is, to be parallel oriented with respect to the spin of the proton.
Based on more than 10 million DIS events collected with a longitudinally polarized deuterium target in 1998-2000, HERMES was able to perform the most precise existing measurement of the g_1d(x) structure function of the deuteron. In a similar manner to g_1p (x), also the structure function g_1d (x) has a maximum around the region of values of x ~ 1/3, but its modulus is lower. An analysis of this result, taking into account the composition of the valence quarks of the deuteron, indirectly highlights the tendency of the d-quark to be negatively polarized (Delta d <0), that is to be oriented anti-parallel to the spin of the proton. In the region at low x (x <0.04), the data of HERMES are compatible with 0, in agreement those of COMPASS, while the data of SMC favor g_1d <0.
Overall, HERMES has added new and more precise data in its kinematic domain to the experiments of first and second generation, in particular for the deuterium target. It is also important to note that the data of HERMES (as well as those of SLAC), were collected at transferred momenta significantly lower than those of previous experiments such as EMC and SMC. This has allowed to perform a comprehensive analysis of the behavior of the polarized structure functions for the whole of the world's data through techniques of perturbative QCD. These analyzes have allowed, besides the indirect derivation of the polarization of quarks of different flavor, also an estimation for the upper and lower limits of the gluon polarization.
The deuteron is a spin-1 object of spin-1 and to fully describe its structure at leading-order level, an additional structure function is required besides to the two describing the proton, namely the so-called b_1 structure function. This is linked to nuclear effects and would disappear if the deuteron consisted simply of a proton and a neutron in a state of relative s-wave. HERMES is the only DIS experiment where it was possible to implement a target that presented tensor polarization, with which it was possible to measure b1 [PRL 95 (2005) 242 001]. The measured value for b_1 has proved be small, but not zero and can be interpreted as a result of the same mechanism that leads to the effect of shadowing in the case of unpolarized deep-inelastic scattering. In practice, the virtual photon is sensitive to the spatial relative alignment of proton and neutron and interacts with the proton interacts first and then with the neutron.
- Semi-inclusive deep-inelastic scattering with longitudinally polarized target.
The main disadvantage of the inclusive reactions is that they are sensitive only to the square of the charge of the quark, but are independent from its flavor and consequently provide only information related to the sum of the spin of the quarks. In order to obtain information regarding the contribution to the spin of the nucleon for each flavor of quarks, it is necessary make use semi-inclusive deep-inelastic scattering reactions (SIDIS) in which, in addition to the lepton, also some of the particles generated in the process of hadronization are detected. The quark which absorbed the virtual photon leaves the nucleus and fragments into hadrons. The observation (of part) of these hadrons can be used as a filter to identify the flavor of the original quark (technique of flavor-tagging). The analysis of the semi-inclusive asymmetries collected in the period 1996-2000 with longitudinally polarized hydrogen and deuterium, has enabled the HERMES collaboration to measure directly for the first time the longitudinal polarization of the u and d valence quarks and of sea quarks s [ PRL 92 (2004) 012005, PRD 71 (2005) 012003]. Confirming the indications of the indirect inclusive measurements, the polarization of the u-quark was positive with greater polarization in large x where the quark valence dominate, while the polarization of the d-quark is negative. The measurements also show that the polarization of the sea quarks is small. Taken together, all these measures show conclusively that the spin of the quarks generates less than half the spin of the proton and that the only contribution comes from the valence quarks.
-Semi-inclusive deep-inelastic scattering with transversely polarized target: transversity
The transverse-spin distribution h_1 is the last piece of the description of the nucleon structure description at leading order: h_1 measures the difference in probability of finding a quark polarized in a direction parallel to the polarization of a nucleon transversely polarized with respect to the direction of motion. It has not been measured directly, as it is a "chirally-odd", and is not accessible through inclusive deeply inelastic scattering. The density h_1 can be extracted from measurements of the spin-asymmetries in the cross-section SIDIS processes between leptons and polarized nucleons in which is a hadron in the final state is detected. In these processes, the measured asymmetry is due to the combined effect of h_1 and another chirally-odd function that describes the process of fragmentation of transversely polarized quarks (the Collins fragmentation function H_1perp .
The HERMES data taking with a transversely polarized hydrogen target, began in 2002 and ended in 2005. The group of Ferrara, thanks also to the support of three approved PRIN-grants, of which Paolo Lenisa was local responsible, was involved in decisive way in the data analysis. The collected statistics has allowed the study of azimuthal asymmetries in the production of pions and kaons. The detected asymmetries are related related to two effects. In addition to the mentioned contribution of the convolution between the transversity distribution h_1 and the Collins fragmentation function, there is a contribution by the Sivers distribution function, linked to a correlation between the transverse polarization of the nucleon and the intrinsic transverse momentum of the quarks. It indicates that the momentum of transverse quark can no longer be neglected in the leading description of the interactions and indicates that the orbital angular momentum of the quarks is different from zero. With the aid of a transversely polarized target, the mechanisms of Collins and Sivers can be separated, because they have different azimuthal dependencies azimuthal with respect to the axis of the transverse polarization. HERMES has published the first single spin asymmetries in the production of hadrons from a transversely polarized target [PRL 94 (2005) 012002, PLB 693 (2010) 11]. The data of HERMES have allowed for the first time to establish that both the processes originating the Collins and the Sivers asymmetries are nonzero. As regards the Collins process, the average momenta moments resulted positive for pi+ and negative for pi- qualitatively in agreement with models that, in analogy with the density of helicity Delta u and Delta d, foresee positive delta u and negative delta d. The azimuthal asymmetries revealed by HERMES in combination with those of the COMPASS experiment at CERN and the results from the BELLE experiment, have allowed to perform the first extraction of the transversity distribution function for u and d quarks, a result that can be considered a milestone for the spin physics.
The observation of Sivers asymmetries [PRL 94 (2005) 012002, PRL 103 (2009) 152002] non-zero was the first direct experimental evidence of a quark orbital angular momentum is not zero. Although a complete and comprehensive interpretation of all the measured asymmetry is not yet available, the data collected allowed the first extraction of the Sivers function for u and d quarks giving indication that the quarks u rotate in agreement with the spin of the proton, while the d quarks rotate in the opposite direction.
- Proponent as co-spokesperson of the PAX experiment at the new facility FAIR in Darmstadt, Germany (2004-2006)
Lenisa Paolo is co-author, as Co-spokesperson of the PAX (Polarized Antiproton eXperiments) experiment proposal for the new FAIR facility at GSI in Darmstadt [hep-ex/0505054]. At the base of the PAX proposal is the possibility of realizing the first intense beam of polarized antiprotons through the technique of spin-filtering in a storage ring.
The availability of a beam of polarized antiprotons would allow the measurements of a series of single and double-spin of asymmetries of spin single and double spin that would allow to access for the first time different physical quantities. For example, such a beam would allow access to the transversity distribution function in a direct and complementary way to the SIDIS measurements. In fact, the azimuthal asymmetries in Drell-Yan pair production generated in the annihilation of transversely polarized protons and antiprotons transversely polarized, depend exclusively on the product h_1 x h_1 and allow its direct measurement. The asymmetry is expected to be of the order of 20-30% in the region where the valence quarks dominate. In addition to the aforementioned transversity function, by measuring the single and double spin- azimuthal asymmetries in the production of lepton pairs from proton-antiproton annihilation the magnitude and phases of the proton electromagnetic form factors of the proton in the timelike region can be derived. Of particular interest is also the study of the role of the spin in the double spin asymmetries in elastic proton antiproton collisions. Such measurement could assist in the interpretation of the asymmetries measured in elastic proton-proton collisions with double polarization which are still lacking a proper theoretical explanation.
The proposal has awaken considerable interest in the international hadronic physics community and received the consent of about 200 physicists belonging to 35 institutions (20 of which are European) that have signed the Letter of Intent sent to the Directorate of GSI in January 2004, followed in January 2005, by the Technical Proposal.
As Spokesperson, Paolo Lenisa followed all aspects of the proposal, especially the issues related to accelerators. Given the complexity of the project, it was necessary to form a real working group dedicated to the machine development. The group included accelerator physicists from Jülich, BNL and Dubna with experience both in the field of polarization and in the colliders.
The implementation of the proposed measurements should be carried out in two stages corresponding to the stages of the system of accelerators. The first phase involves an experiment in which the polarized antiprotons, after production in a dedicated polarizer ring, are stored in another ring, accelerated up to a momentum of 3.5 GeV/c and then made to collide on a polarized internal gas target. The kinematic conditions offered by this solution are ideal for the study of form factors and elastic collisions. A ring of these characteristics has been identified in the ring COSY, currently in operation at the FZJ in Jülich, which will be decommissioned after 2015. The second phase involves the construction of an asymmetric proton-antiproton collider with double polarization. The storage of antiprotons and protons in the COSY and HESR rings respectively, planned for the FAIR facility with a maximum momentum of 15 GeV/c, would result in collisions with an energy in the center of mass energy of about sqrt (s) ~ 15 GeV, which is ideal for the study of transversity.
The long timeline of the experiment and the necessary priority given to the complete understanding of the process of polarization of antiprotons. finalized in a series of dedicated experiments presented below, have limited the study of the detector at the level of conceptual design. Fundamental element of the detector is represented a toroidal magnet which present zero field along the axis of the beam and allows in the first phase of the experiment the use of an internal target polarized with the possibility of directing at will the magnetic axis of quantization.
The physics program of the PAX experiment was judged as excellent by the Program Advisory Committee of the FAIR facility. However, the implementation of the PAX experiment within the facility was subject to the demonstration of feasibility of the proposed technique to produce polarized antiprotons: the spin-filtering. The confirmation of the polarizability of a stored proton beam by spin-filtering, and the demonstration that this mechanism as the only able to polarize the nucleons accumulated in a ring has been recently achieved with a series of experiments dedicated realized ring COSY the FZJ-Juelich. Paolo Lenisa is one of the promoters of this series of experimental initiatives related to the study of the mechanisms of production of a beam of polarized antiprotons. His activity 'in this field is briefly reported below. In the framework of his collaboration with the COSY-Juelich FZJ Lenisa Paolo Lenisa has acted as Spokesperson of an International Collaboration.
- Ideation preparation and management as Spokesperson of a depolarization measurement of a beam of protons at the COSY storage ring at FZJ-Jülich (2007-2008).
Two possible principle ways exist to polarize a beam of a spin 1/2 particles, as antiprotons, stored in a storage ring. The first, called "spin-flip" is based on the existence of a mechanism that gives rise to a different transition probabilities between up and down states with respect to the opposite process. The second, called "spin-filtering", involves the use of a process that selectively removes from the storage ring one state with respect the other.
This framework justifies a depolarization measurement of a beam of protons, performed at the COSY-storage ring of the Forschungszentrum Juelich in 2008. The experiment was motivated by the possibility of experimentally proving a proposal of an innovative method to polarize an antiproton beam by making use of the spin exchange interaction with a polarize co-moving positron beam (technique of spin-flip). This proposal was put forward by a group of physicists at the University of Mainz in 2007. Despite the limited intensity for a polarized positron beam obtainable with current technology, the proposal was of interest for the high cross sections of spin-exchange calculated by the proponents (> 10^13 barn). The method offered itself to a favorable experimental evidence at the COSY ring. With respect to the proposal, in the performed experimental test, both the charge of the two beams have been reversed (protons and electrons were used instead of antiprotons and positrons), and the role of the beams themselves. In the measurement, use has been made of the principle that if the transfer mechanism is active to transfer spin polarization from an initially polarized positron (electron) - beam to an initially unpolarized antiproton (proton) - beam, then the same mechanism must be active to depolarize an initially polarized antiproton (proton) - beam by interaction with an initially unpolarized positron (electron) - beam. The COSY ring offered the ideal experimental conditions for carrying out such a test, having at disposal polarized proton beams and an electron cooling system capable of producing a beam of unpolarized electrons with the possibility of varying in a controlled way the relative velocity between the electron and proton beams.
The limited energy range of the COSY electron cooling system, has driven the execution of measurement at the injection energy of the proton beam (45 MeV). The measurement cycle itself has been organized into two phases. In the first phase, that of depolarization, the electron beam has been alternately tuned and de-tuned in energy with respect to the proton beam. Such alternation had the aim of avoiding to degrade the characteristics of the proton beam in the depolarization phase. The theoretical estimates included in fact a cross section maximum (and therefore the maximum effect of depolarization) for relative kinetic energies between the proton and electron beams of about 2 keV. In this condition, the electron beam ceases its cooling function and the proton beam begins to heat up. In order to avoid this effect, the time of detuning of the electron beam with respect to the nominal energy has to be limited. A preliminary test performed in November 2007, prior to the measurement made in February 2008, has allowed us to determine the ideal time for the alternation of the two beam energy conditions in intervals of 5 seconds. In the second phase of the measurement cycle, the beam polarization was measured using by making use of the single-spin asymmetries generated in elastic scattering of the proton-beam off a deuterium target. For this purpose use has been made of the cluster-target of the ANKE experiment. In order to reveal the left-right asymmetry in the recoil deuteron, a system of two telescopes realized by silicon detectors has been installed. The positioning of the detector has been determined by optimizing the figure of merit of the diffusion reaction (square of the product of the analyzing-power times the cross section), while the thickness of the silicon detectors (300 microns) has been chosen so to ensure the identification of deuterons from protons. Implementation of the detector has been handled by the Juelich group. The Ferrara electronic workshop, under the coordination of Paolo Lenisa, contributed to the commissioning of the readout electronics (Paolo Lenisa is Tutor of dedicated PhD thesis) and of the development trigger-board successfully used during the measurement.
The measurements itself showed no effect of depolarization of the beam within the statistics acquired during the experiment. The negative outcome resulted in the expression of an upper limit to the spin-transfer cross section related to the depolarization effect effect. This limit was set at 5 x 10^7 barn which makes the proposed method not applicable, also considering possible future technological developments in the intensity of the sources of polarized positrons. The measure has been the subject of publication in an international journal [PLB 674 (2009) 269].
Paolo Lenisa, besides having taken care of the scientific aspect of the experimentation, has been active in searching for the financial support of the activity. The Italian component of the collaboration has been supported besides by INFN (Paolo Lenisa is the national scientific responsible for the PAX experiment), by a Joint Research Activity (I3HP2) funded by the European Union for the period 2008-2011. Part of the Work-Package (WP 25: PolAntiP) of the JRA, for which Paolo Lenisa is local responsible, was actually motivated by the mentioned depolarization studies. With the funds of the financing, the unit of Ferrara has supported three annual grants dedicated to the development of the experimental apparatus and analysis of the collected data.
- Design, preparation and management as Spokesperson of a of spin-filtering measurement at the COSY ring (2009-2011).
The experimental demonstration that the spin-flip technique could not be used to polarize a stored antiproton beam, has left as the only option the use of the spin-filtering mechanism. For this reason, in April 2009, Paolo Lenisa as Co-Spokesperson of the PAX Collaboration, has promoted a spin-filtering experiment with protons at the COSY-ring in Juelich. Aim of the measurement was twofold: to confirm the theoretical knowledge of the spin-filtering mechanism on the one hand, and to commission the experimental apparatus for a possible subsequent test with antiprotons on the other.
The preparation phase of the measurement had a duration of nearly three years, that have been used to install and commission the required experimental apparatus inside the ring COSY. The interaction region devoted to a spin-filtering experiment consists of three basic elements: a) a set of quadrupole magnets for the realization of a low-beta section where to install the storage cell with the polarized gas; b) a polarized internal target with its polarimeter and c) a beam polarimeter.
The magnets used for the realization of the interaction point were recovered from the decommissioning of the CRYRING-ring at Stockholm. For the realization of the target, use has been made of the apparatus of the HERMES experiment, properly updated, while the beam polarization was measured by the asymmetry in the elastic scattering events detected by a couple of silicon-telescopes managed by the ANKE Collaboration, and previously used for the depolarization experiment.
An important phase of the experiment commissioning was devoted to accelerator studies and improvement of its performance. In the context of a spin-filtering experiment and the final polarization induced in the beam, a key parameter is the average beam lifetime. Thanks to a series of dedicated machine studies and improvements of the vacuum conditions of the ring, the average beam lifetime has been improved by a factor greater than 20, bringing it to a value of tau = 8000 s which was the one used in measurement. (A dedicated paper is in preparation).
The spin-filtering test with protons has been finally performed in the Autumn 2011. Aim of the experiment was the measurement of the spin dependence of the proton-proton cross section in the case of transverse polarization. To this aim a dedicated spin-filtering cycle has been implemented in the ring. As first step, an unpolarized proton beam is injected in the ring, the beam is then cooled (by electron cooling) and accelerated to the energy of the measurement. At this point the polarized target is "switched-on" and the spin-filtering process starts. The duration of this phase, amounting to 1.5 – 2 beam lifetimes, has been determined to optimize the statistic for the following phase of the experiment: namely the measurement of the beam polarization. Finally, the polarized target is switched-off, and, in another section of the ring, an unpolarized deuterium target is “switched-on". The polarization induced in the beam is measured through the identification of elastic scattering events by means of a pair of silicon telescopes.
Combining the induced polarization in the beam with other information such as the polarization and density of the target, and the revolution frequency of the particles in the ring, it was possible to determine the polarized interaction cross-section polarized in the case of transverse proton-proton interaction. The result is in excellent agreement with the theoretical predictions and represents a milestone for the concerned research. On the one hand confirming the current understanding of the spin-filtering process and on the other demonstrating a complete control of the ' experimental apparatus and its systematic uncertainties.
As Co-Spokesperson of the PAX Collaboration, Paolo Lenisa followed and directed all phases of the experiment from the proposal, to the organization of the Collaboration, the commissioning of the apparatus, the performance of the measurement and, finally, the analysis of collected data. The experience and knowledge gained by Paolo Lenisa during the HERMES experiment, allowed the use of some of the resources of this experiment that completed its data taking in 2007. In particular, the polarized target and its polarimeter were transported in Juelich and put into operation after an appropriate update. From the organizational point of view, several working groups have been established engaged in the different design and implementation activities. In addition to the three cited: target, detector and accelerator, additional working groups were formed around the activity related to data acquisition, control and analysis of the collected data and their theoretical interpretation. Each working group was managed by a coordinator. The responsibilities of the various groups were distributed according to the competence of the various institutes of the collaboration taking part to the experiment: in addition to Ferrara and Juelich, these include also Bari, Dubna, Erlangen, Mainz, St. Petersburg, for a total of about 50 "active" participants. In addition to through regular meetings, the coordination of the activity of Collaboration has been accomplished by the extended use of teleconferencing (via Skype) and the introduction of a wiki page to facilitate the exchange of documents and information between the different groups (http://apps.fz -juelich.de/pax/paxwiki/index.php/Main_Page).
The work is described in the three dedicated publications dedicated: one devoted to theoretical calculations, one to the machine preparatory studies and one dedicated to the measurement itself (accepted for publication on Phys. Lett B). Paolo is Lenisa is tutor of two doctoral theses related to the preparation and the implementation of the measure.
Paolo Lenisa, besides having taken care about the scientific aspect of the experimentation has been active in fundraising for the financial support of the activity. The Italian component of the collaboration has been supported besides by INFN, by an Advanced Research Grant (POLANTIP) funded by the European Research Council for the period 2010-2015 of which Paolo Lenisa is scientific responsible for the unit of Ferrara. As part of this project 5 post-doc grants and 3 contracts for technical collaboration have been funded through the University of Ferrara.
- Proponent as Co-Spokesperson of the measurement of the spin-dependence of the proton-antiproton cross section at the AD ring at CERN AD (2009).
Simultaneously with the submission of the proposal of the spin-filtering experiment with proton at the COSY ring, the PAX Collaboration has submitted a Technical Proposal to the CERN SPS Committee to make the first measurement of the spin dependence of the proton-antiproton cross section. Such knowledge would allow the design of a dedicated a storage ring to polarize an antiproton beam through spin-filtering. The current theoretical predictions for the spin dependence of the proton-antiproton cross section, are dominated by the uncertainty in the description of the annihilation process and are conflicting with each other by a factor 2, which requires a direct measurement. The AD ring at CERN is the only machine in the world which presents an energy range favorable to filtering spin with antiprotons (between 50 and 500 MeV).
The PAX Collaboration has proposed the installation of the experimental apparatus for the measurement, in one of the four straight sections of the ring. In the drafting of the proposed experiment, particular attention was paid to the compatibility with the experiments already operating on the AD ring and performing delicate measurements related to antimatter. For this reason, the planning foresees an installation of the experimental apparatus divided into three phases, the success of each of which constitutes the necessary condition for the transition to the next. The first phase involves solely the installation of additional quadrupoles in a straight section of the ring for the realization of a low-beta section, without altering the existing magnetic structure. Once ensured the reproducibility of the performance of the machine for the other experiments with use of the new quadrupoles, one should switch to the next installation step comprising the removal of the existing quadrupole placed at the center of the straight section to make room for the scattering chamber of the PAX experiment. Only in the last and third phase, foresees the installation of the experimental apparatus. This includes: a polarized atomic source, a storage cell, surrounded by a silicon telescopes detector to measure the beam polarization a the Breit-Rabi polarimeter to measure the target polarization. Currently, the proposal is being considered by the Committee at CERN SPS which is evaluating the impact on the programming and testing that has already been approved at the AD ring.
- Co-proponent and team leader of Ferrara of the OLYMPUS experiment at DESY in Hamburg for the measurement of two-photon contribution to the proton electromagnetic form factors.
Some measurements of the proton electromagnetic form factors carried out at the JLAB Laboratory (Virginia, USA) in the early 2000 through the polarization transfer technique, showed an unexpected and dramatic discrepancy with the measurements made by the well-established Rosenbluth unpolarized cross-section separation technique. The discrepancy could be explained by introducing the exchange of more photons in the calculation of the elastic electron-proton cross section over the traditional single-photon approximation. An experimental confirmation of this theoretical interpretation is very important since most of the present understanding of the structure of the proton and of atomic nuclei relies on the diffusion of leptons analyzed through single photon approximation.
For this reason, in September 2008, the OLYMPUS Collaboration has submitted an experimental proposal to the Physics Research Committee of DESY in Hamburg. The OLYMPUS Collaboration, of which Paolo Lenisa is scientific responsible for the unity of Ferrara, consists of 50 physicists from Germany, Italy, Russia, United Kingdom and United States. The experiment aims to measure accurately the ratio of the cross sections for elastic collisions between positron-proton and electron-proton. The most direct evidence for a multi-photon exchange is inferred by the deviation from the unit of this ratio. The experiment uses the intense beam of electrons and positrons of the DORIS ring incident with an energy of 2.0 GeV on a target of molecular hydrogen stored in a storage cell placed in the beam line. The detector of the experiment is constituted by the large acceptance toroidal spectrometer of the BLAS experiment, (MIT-Boston, USA). After the completion of the installation in 2010-11 and the successfully completed commissioning in early 2012, the experiment will acquire two months of dedicated data taking in winter 2012. The ultimate goal is the measurement of the ratio of cross sections with an accuracy better than 1%.
The Participation of Ferrara to the Collaboration has been specifically requested by the other members of the Partnership, some of which were previous members of the HERMES experiment, thanks to the acknowledged competence of the group of Paolo Lenisa in the realization of the storage cells. Such a device, realized through a properly shaped sheet of aluminum with a thickness of 75 microns, is one of the most delicate points of the whole experimental apparatus, especially in a hard environment such as that of an electron storage ring.
- Co-proponent of an experiment for the measurement of the electric dipole moment of the proton and deuteron in a storage ring and Spokesperson of a measure of the longitudinal spin-coherence time of a polarized beam at the COSY storage ring.
Giving continuity to the skills acquired in the control and management of systematic involved in polarized beams Paolo Lenisa has recently devoted his interest to a proposal of measurement of the electric dipole moment (EDM) of the proton and deuteron in a storage ring [C.10]. A intrinsic non-zero EDM in these particles would violate both parity P and time-reversal symmetry, which, assumed CPT invariance, would give an indication of CP violation. It is well established that the CP violation sources in the standard model are not sufficient to explain the matter-antimatter asymmetry in the universe and the search for mechanisms of CP violation is one of the frontiers of the new physics. The predictions of the standard model for the electric dipole moment of particles such as the proton and deuteron are well below the measurable experimental limit, the situation is different for the predictions of models of physics beyond the standard model that are well inside the experimental reachable sensitivity.
The search for an EDM in a storage ring is a relatively recent and is strictly linked to the technological developments of polarization in storage rings themselves. The measurement technique involves the injection in the ring of a beam longitudinally polarized along the direction of the velocity of the beam itself. Through a particular configuration of electric and magnetic fields in the ring, it is possible to inhibit the precession of the spin of the particle with respect to the momentum (condition of "frozen-spin"). In this condition, the signal of an EDM different from zero is represented by the precession of the polarization direction from longitudinal to vertical, under the influence of a strong electric field in the reference system of the beam itself. At a level of sensitivity of around 10^(-29) e cm, the signal of the EDM would be represented by a precession of the order of 10^(-5) rad after a storage time of 20 minutes. The observation of this small change in the polarization of the beam requires a number of conditions. A fundamental requirement is that the polarization of the beam remains high during the 20 minutes requested to accumulate a measurable signal. The availability of polarized beams of protons and deuterons and of the related polarimetry, makes the ring COSY a unique environment to study the influence of various parameters of the beam on the polarization lifetime. For this reason, a dedicated program has been initiated to study the effect of various parameters of the lifetime of the longitudinal beam polarization, or, more properly on the spin-coherence time. In this context, Paolo Lenisa is co-Spokesperson of a program of measurements devoted to the determination of the spin-coherence time at the COSY ring. One of the effects that we intend to study the influence of the synchrotron and betatron oscillations of on the spin-coherence time and the possibility of compensating for these effects through the use of radiofrequency cavites and sextupoles.
- Co-proponent and responsible for the PAX Collaboration of the TRIC proposal for a test time-reversal invariance at the COSY ring of the FZ-Juelich
Unlike the search for an intrinsic electric dipole moment, the existence of which would violate simultaneously both parity and time invariance, the TRIC (Time Reversal Invariance at COSY) experiment is aiming to test the time-invariance (Time Reversal Invariance, TRI) in a situation in which the parity is preserved. An observable on which to perform such verification has been identified in the proton-deuteron spin-correlation A_(y,xz) in which the vector polarization of the proton P_y is oriented along the y direction and the tensor polarization of the deuteron P_xz, according to the direction xz.
This test offers itself to a favorable experimental verification inside a storage ring. In fact, using the property of parity conservation of the variable under observation, the verification may be performed by comparing the total transmission cross sections of a polarized proton beam stored in the ring through a internal polarized deuterium target. A difference in the total cross sections of interaction of the beam with the target obtained by reversing the direction of one of the two polarizations, would constitute an indication of time-invariance violation. That statement is immediately translated into a different lifetime of the stored beam, and the experiment can be practically traced to a precise measurement of the beam current into the storage ring.
Particularly attractive is the situation at the COSY ring, where the measurement can be realized with the complete re-use of the experimental apparatus developed for the PAX-experiment PAX (target and relative polarimeter implemented with a large acceptance detector for the determination of the beam polarization). The experiment also will benefit of the machine studies performed by the PAX collaboration that led the ring to its present excellent performance with regard to the beam lifetime and polarization. The only important additional implementation to existing apparatus, is constituted by a high-precision beam current monitor. In order to achieve the necessary accuracy, from which the accuracy of the entire measurement depends, the plan is to make use using cryogenic current comparators employing the SQUID technology.
After a feasibility study carried out in late 2012, the experiment foresees to start dedicated data taking in 2015, when the large acceptance detector will be completed and the new beam current monitor installed in the COSY ring.
- Promoter of a scientific cooperation agreement between INFN Ferrara, the Nuclear Physics Institute (PNPI), Gatchina, Russia, and the FZJ (Juelich, Germany) for the study of fusion reactions of light elements with polarization of the initial particles .
Paolo Lenisa is the promoter of an agreement for scientific collaboration between INFN Ferrara, the Nuclear Physics Institute (PNPI), Gatchina, Russia, and the FZJ (Juelich, Germany) for the study of fusion reactions of light elements with polarization of the initial particles.
The project aims to extensively study the differential cross section of the reactions d + d -> t + d and d+d -> n-3He with polarized incoming deuterons in the energy range 10-100 keV. In particular the aim is to study the influence of the polarization vector and tensor on the total fusion cross-sections and the branching ratio of the two channels. A direct experimental measurement is quite important given the discrepancy between the different theoretical predictions. The study is also important from the point of view of the possible applications of advanced fusion power-plants employing polarized particles. An increase of the polarized reaction to the non-polarized, would allow a reduction in the size of the vessel, at the moment in which density of polarized particles comparable with the unpolarized case could be reached. In addition, a different branching-ratio in the fusion two channels, such as the suppression of the neutron channel as predicted by many theoretical works, would decrease the damage by neutron radiation and allow for an extension of time of operation of the future generation of fusion reactors.
The experimental apparatus involves the use of a beam of polarized deuterons accelerated to a suitable energy incident on a polarized atomic deuterium target. The reaction products will be analyzed using a large acceptance detector realized with silicon diodes. As part of the collaboration, the deuteron source is provided by the German part of the collaboration, while the Russian side is providing the detector. The contribution of Ferrara consist in the polarized atomic source. It is expected to move the atomic source presently located in the Ferrara Labs to Gatchina by the beginning of 2013. After a period of adaptation of the source and commissioning of the entire experimental setup, the data taking is expected to start in 2014.
PART ll: ADMINISTRATIVE ACTIVITY AND MANAGEMENT
In order to provide the necessary financial support to its research team and the appropriate scientific framework of his group in the national and international research community, Paolo Lenisa has become promoter and coordinator of various projects related to funding requests at national and international level.
At the Italian national level, Paolo Lenisa, since 2005, the national scientific responsible of the PAX-experiment inside INFN. He was also coordinator for Ferrara of three research projects PRIN (2003, 2006, 2008) funded by the Ministry of Education dedicated to the study of transversity of the nucleon. At the international level, Paolo Lenisa was and still is responsible for the University of Ferrara of three work packages of the Joint Research Activities - I3HP2 and I3HP3 and of an Advanced Research Grant financed by the European Commission within the VII Framework Programme, linked to research on polarized antiprotons.
- 2003 - 2005: Responsible for the research unit of Ferrara of the PRIN 2003 project approved and funded by MIUR: "Study of SIDIS reactions ep -> e'hX for the analysis of transversality 'of the nucleon."
Paolo Lenisa was responsible for local project PRIN - 2003 approved by the Ministry of Education in 2003 dedicated to the theoretical and phenomenological investigation of transversality of the nucleon. The project involved theoretical and experimental physicists of the Italian universities of Como, Ferrara, Trieste and Turin, involved in the experiments HERMES and COMPASS. To the Research unit of Ferrara belonged physicists and graduate students of the University of Ferrara and the National Laboratories of Frascati.
The transverse spin distribution h_1 is the last missing piece in the partonic description of the nucleon aat leading order: h_1 measures the difference in probability of finding a quark polarized in a direction parallel and opposite to the polarization of a nucleon transversely polarized with respect to the direction of motion. The h_1 distribution function has never been directly measured, since it is a "chirally-odd" fnction, and is absent in inclusive deeply inelastic scattering. The density h_1 can be extracted from measurements of cross section spin-asymmetries in semi-inclusive deeply inelastic scattering processes (SIDIS) of leptons and transversely polarized nucleons which also reveals a hadron in the final state. In these processes, the measured asymmetry is due to the combined effect of h_1 and another chirallly-odd function, which contributes to the fragmentation of transversely polarized quarks. In the case in which the final observed hadron is a pion or, in general, a scalar particle, this new function of fragmentation is the so-called Collins, and, at the time of the project, not yet measured. The HERMES data taking with a transversely polarized hydrogen target began in 2002 and ended in 2005. The collected statistics has allowed the study of non-zero azimuthal asymmetries with transverse target. These asymmetries, that the Unit of Ferrara has significantly contributed to analyze, are related to two effects. The first, represented by the distribution of Sivers, is related to a correlation between the transverse polarization of the nucleon and the intrinsic transverse momentum of the quarks. It indicates that the transverse momentum of the quark can no longer be neglected in the leading description of the interaction and indicates that the orbital angular momentum of the quarks is different from zero. The second effect is due to the convolution between the transversity distribution h_1 and the Collins fragmentation function that relates the transverse momentum of the leading hadron to the spin of quarks that produced it. Both functions were not measured at the time of the project. The measurements performed with the transverse target made it also possible to quantify the contribution of higher-order twist to the azimuthal asymmetries measured with longitudinal target.
The financing of about 70 keuro was used to fund three research annual grants devoted to the analysis of the HERMES data.
- 2006 - 2008 Scientific responsible for the research unit of Ferrara for the PRIN 2006 project approved and funded by MIUR: "Study of transverse spin in the nucleon through semi-inclusive DIS reactions ep -> e'hX, Drell-Yan processes pbar p -> l + l-and pbar p elastic scattering. "
The new aspect of the PRIN project submitted and approved in 2006 compared to 2003 is the proposal to unambiguously measure h_1 linked to the PAX experiment. The PAX proposal, "Polarized Antiproton Experiments", is part of the "Facility for Antiproton and Ion Research" (FAIR) of a large European laboratory for the study of hadronic physics planned at Darmstadt. The proposal is based on the possibility to obtain for the first time a high-quality beam of polarized antiprotons, for the study of transverse spin effects of the nucleon through Drell-Yan (DY) processes and pbar-p elastic scattering. The Drell-Yan pbar p -> e+ e- is a complementary approach with respect to SIDIS that allows a direct and unique measurement of transversity distribution function and to verify the change of sign foreseen for the Sivers-function compared to DIS. The use of an internal polarized target similar to that of HERMES one internal to the beam line and the creation of a pbar p-polarized collider will allow to detection for the first time of double polarized Drell-Yan reactions. The spin asymmetries in this case depend only from h_1 and do not require the concomitant presence of another chirally-odd quantity: h_1 appears twice in the reaction, one for each interacting nucleon. Transverse polarized DY can be studied also in RHIC (Relativistic Heavy Ion Collider) at Brookhaven National Laboratory, but only in proton-proton reactions of high energy. In this case the transverse spin asymmetries depend on the convolution of two different transversity functions – h_1 (quark) and h_1 (antiquark), measured in the region of low x-Bjorken where they are expected to be very small (of the order of 0.01). In contrast, PAX uses antiproton-proton reactions where the asymmetries depend on the simple product of h_1 (quark) with itself, and plans to explore the energy region of the valence quarks, where the asymmetry and large (of 'order of 0.3).
The working project of the Ferrara research unit, coordinated by Paolo Lenisa, was expected to contribute to some of the most promising HERMES analysis in different channels of semi-inclusive DIS, which at a theoretical level, are supposed to be sensitive to transversity, and also to provide feasibility studies and optimization in preparation for the future measurement of the PAX experiment, as ideal continuation of the present research.
The total funding of 60 keuro was used for the funding of two annual research grants devoted to the analysis of the HERMES data and the simulation of Drell-Yan events in double polarized proton-antiproton annihilations.
- 2010 - 2012 Scientific responsible for the research unit of Ferrara for teh PRIN 2008 project approved and funded by MIUR: "Study of the effects of spin and transverse momentum in the nucleon through semi-inclusive DIS reactions ep -> e'hX, processes of Drell- Yan pbar-p -> l+ l- and pbar-p elastic scattering. "
The activity of theoretical and phenomenological investigation of the PRIN 2003 and 2006 was revived with success in 2008. Indeed, despite the enormous progress in the latest years, there are still many unclear points about the internal spin-structure of hadrons and polarized fragmentation functions, related to non-perturbative properties of hadrons, that cannot be calculated in perturbative quantum chromodynamics (pQCD) but which can be estimated through phenomenological models or experimentally measured.
Of the three basic distributions that characterize at leading-order, the state of the quarks in the nucleon, the unpolarized distribution is known with great accuracy, the helicity distribution (longitudinal spin) has been measured with good precision, but in a limited kinematic range, while the transverse spin distributions, as the transversity h_1, have not yet been directly measured, although experimental information indirect start to be available. These results allowed a first extraction of h_1
The study of transverse spin effects in the nucleon has shown that the transverse component of momentum (transverse momentum) can no longer be neglected in the description of the interactions; the non-trivial correlations between the transverse components of the momentum and the spin generate unexpected effects that can open new scenarios on the internal dynamics of the nucleon and described by new transverse momentum - dependent partonic functions (TMDs). The new time-reversal odd (T-odd) correlation functions are sensitive to transverse spin effects that currently subject of great interest. The fragmentation functions, such as those sensitive to the quark polarization, are not only indispensable for the extraction of transversity h_1 in semi-inclusive DIS reactions, but are also of great interest in itself, because they describe the process of hadronization, or in other words, the origin of the quarks’ confinement.
Of great importance are the new T-odd parton distributions, such as the Sivers functions that relate the transverse momentum of the quarks to the spin of the nucleon to which they belong and therefore involve the orbital angular momentum of partons, or the Boer-Mulders functions that correlate momentum and transverse spin of quarks in unpolarized nucleons and involve the spin-orbit partonic effects.
In the framework of the MIUR project, the activities of the research unit of Ferrara, is oriented to the study of transverse spin distributions and the corresponding fragmentation functions of the nucleon, the finalization of the most promising HERMES analysis in different channels of semi-inclusive DIS, that at the theoretical level are considered to be sensitive to transversity and TMDs, and finally to a contribution to the approved experiments at Jefferson Lab with a beam of 6 GeV, relevant to this type of investigation.
The total funding of 50 keuro was used for the funding of two annual research grants annual dedicated to the conclusion of the data analysis undertaken within the HERMES experiment.
- Since 2005: National scientific responsible for the PAX experiment in the INFN National Scientific Committee III
In order to provide financial and logistical support to the activity of the PAX Collaboration, Paolo Lenisa requested and obtained the opening of a code for the PAX-experiment in the Commission III INFN. Paolo Lenisa, since 2005, is the national (and local Section of Ferrara) responsible for the PAX experiment. At the PAX experiment pertain researchers from Ferrara and Bari – INFN sections. Over the period 2005-2012, the PAX-INFN code has always had an annual average of ten full-time equivalent related.
The INFN contribution was crucial both for the Italian participation and for the overall management of the experiment. In the dual role of Co-spokesperson of the PAX Collaboration and national scientific responsible inside lNFN, Paolol Lenisa was able to coordinate the contribution of INFN synergistically with that of the rest of the Collaboration, represented mainly by the German Forschungszentrum Juelich. While the contribution of the FZJ has been finalized to developments related storage ring, the Italian INFN funding was mainly focused on relevant issues more related to the experimental apparatus. In particular, it should be mentioned:
- Moving, updating and implementation of the polarized target and the Breit-Rabi polarimeter of the HERMES experiment at DESY in Hamburg to Forschungszentrum-Juelich. Ferrara is responsible for managing the polarimeter within the Collaboration. In collaboration with the Section of Bari a new interlock and slow control system for the polarimeter based on LabView has been designed and implemented.
- Design and implementation of a new trigger system for the PAX experiment. Thanks to the work of the Ferrara electronic workshop a new trigger board has been designed, built and commissioned to replace the existing obsolete system at the FZJ based on NIM modules.
- Development of a test bench for Silicon detectors in Ferrara. This system includes a vacuum chamber offering the option to perform energy calibrations of the detectors.
- Design of a large-angle detector for the future activity of the Collaboration and prototyping activities of the key components (eg cooling).
- Contribution to the purchase of silicon detectors to complete the construction of the detector that foresees also the reuse of some silicons from the recoil detector of the HERMES experiment.
- Purchase of electronic boards for the detection system
In total, including support for travel costs, the INFN contribution of the experiment overcomes the million euro over a period of six years.
- 2007 – 2010 Local scientific responsible of Virtual Institute of European universities funded by the Helmholtz-Gesellschaft: "Virtual Institute on Spin and Strong QCD".
Lenisa Paolo was responsible for the research unit of Ferrara for the Virtual Institute "Spin-physics and Strong QCD" funded by the Helmholtz Gesellschaft. The Virtual Institute is composed by 7 universities and research institutes of Europe (Germany, Italy, Switzerland, Poland) which are centers of excellence in the field of hadronic physics and spin. The Institute was supposed to support such research by granting international travels of the physicists involved in the research, both theoretically and experimentally. The obtained financing, 60 keuro in three years, has made it possible to offer substantial support for the participation of foreign physicists, especially students, to two workshops organized in Ferrara where Paolo Lenisa acted as Chairman Lenisa ("Transversity 2008" and "PST2009" described later). The grant also allowed to finance the stay at the University of Ferrara of foreign researchers involved in the research.
- 2008-2011 Scientific responsible for the unit of Ferrara of the Joint Research Activity "Hard-Exclusive Reaction (Hardex)", Work Package-23 in the framework of the Project "Hadron Physics 2" (I3HP2) funded by the European Community within the VII Framework Program.
Lenisa Paolo was scientific responsible for the INFN Ferrara of Work-Package 23 in the JRA I3HP2 (Coordinator Carlo Guaraldo) funded by the European Community. The work package collected European physicists from different institutions involved in several, taking data and future experiments (HERMES, COMPASS, PANDA, JLAB). The purpose of the project was the management of a coordinated action of the various experiments dedicated to the study of exclusive reactions as a tool to access the Generalized Parton Distributions of the Nucleon (GPDs). Task of the unit of Ferrara was to investigate the possibility of installing a polarized hydrogen target in the PANDA experiment planned to be installed in the HESR ring at the future FAIR facility. Such an experimental situation, would allow the access to different physical observables via single-spin asymmetries in proton-antiproton annihilations. Among the possible measurements, worthwhile to be mentioned is the phase of the proton electromagnetic form factors in the time-like region. The installation of a polarized target in the detector of the PANDA experiments represents a particularly difficult task, due to the presence of the solenoidal magnet. that, in the absence of adequate measures, limits the state of polarization of the target to the longitudinal direction.
The total support of about 60 kEuro has been used to support a two-year research grant for the study of a suitable configuration of magnetic fields providing the proper shielding of the solenoid with a counter-solenoid. At the same time we studied the possibility of realizing the containment field of the target, through the use of high-temperature superconducting magnets installed on the support of the storage cell of the polarized target.
- 2008-2011 Scientific responsible for the unit of Ferrara of the Joint Research Activity "Polarized antiprotons (PolAntiP)", Work Package 25 of the project "Hadron Physics 2" (I3HP2) funded by the European Union under the VII Framework Programme .
Lenisa Paolo has been scientific responsible for the INFN Ferrara of the Work-Package 25 (PolantiP) in the JRA I3HP2 (Coordinator Carlo Guaraldo) funded by the European Community. Aim of the activity was to support the activity developed at the COSY ring, related to the production of polarized antiprotons. In particular, two were the objectives of the project: the studies of depolarization of a beam of polarized protons by interaction with an unpolarized electron beam (described earlier), and the a spin-filtering test to polarization of a stored proton beam (also previously described). Both objectives were successfully completed within the timeframe of the project.
The total funding of about 60 keuro was used to fund two research grants dedicated to the development of acquisition electronics of the experiment and to fund travel expenses of members of the group in Germany.
- 2012 - 2014 Scientific responsible for the unit of Ferrara of the Joint Research Activity "Polarized antiprotons (PolAntiP)", Work Package 25 of the project "Hadron Physics 3" (I3HP3) funded by the European Commission within the VII Program framework.
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The project represents the continuity of the one completed in the previous three years. Goal is the completion of studies on proton spin-filtering with a measurement obtained with a longitudinally polarized target. This measurement is justified both from the point of view of physics involved (the interaction cross sections for transverse and longitudinal polarizations are independent of each other) that from that of the involved technology. In fact, the spin-dynamics of a longitudinally polarized stored beam is completely different from that of a vertically polarized beam, moreover also the measurement of the polarization induced in the beam requires a different type of detection technique.
For a proper synergic coordination of the various financial supports to the activity, most of the amount of the fund (about 60 keuro) has been assigned to the travel expenses (particularly at the ring COSY) for the Ferrara group.
- 2010-2015 Scientific responsible for the unit of Ferrara for the Advanced Research Grant "POLPBAR" financed by the European Research Council within the VII Framework Programme.
The research activity on the production polarized antiprotons has received a further important recognition by the European Research Council, represented by the acknowledgement of an Advanced Research Grant for a total funding of 2.5 Meuro. Purpose of the Grant is to support the spin-filtering with protons at the COSY and those on antiprotons at the AD ring at CERN. The measurement of the transverse polarizing cross section has been successfully completed in the first phase of the project and that in the next future will include a measurement with longitudinal polarized target at the COSY-ring. For the possible measureents with antiprotons at the AD ring is necessary to wait for the reply of the CERN SPS Committee to the PAX Proposal. Principal Investigator of the Proposal is prof. Hans Stroeher, director of the 'Insitute fuer Kernphysik II of the Forschungszentrum Juelich. In addition to the unit of Ferrara, partner in the project is the Laboratory for Nuclear Physics in Dubna.
The financing for the research unit of Ferrara, coordinated by Paolo Lenisa, is of approximately 600 keuro. The funds were crucial to finance the labor force of the project. Within the five years of the project, this will involve the funding of 10 Post-Doc annual grants and 4 contracts for technical cooperation.
PART III: ORGANIZATIONAL ACTIVITY
To support and disseminate in the scientific community his line of research, Paolo Lenisa has promoted and organized various International Schools and Workshop, three of them as Chairman, two of which were held in Ferrara. In the following we describe the contributions to the main ones. The full list can be found in the introduction to this CV.
- Co-chairman of the 409.WE Heraeus-Seminar: "Polarized antiprotons" - Bad-Honnef, Germany, 23 - 25 June 2008 (http://www.fe.infn.it/heraeus/
Paolo Lenisa organized as Co-chairman the Seminar "-Polarized antiprotons" that was held at the Physik-Zentrum Bad-Honnef in Germany 23 to 25 June 2008. The Workshop was organized with the aim to explore the potential applications of polarized antiprotons in the field of hadronic physics and at the same time to point out of the current status on the possible mechanisms involved in the production of a beam of polarized antiprotons both form the experimental and theoretical points of view. For this purpose the workshop hosted the leading international experts in the field. The workshop was also an opportunity of training for young students and researchers with an interest in nuclear and hadronic physics. The event was organized with the support of the German foundation Heraeus and was attended by about fifty European physicists. Paolo Lenisa, as co-chairman, was responsible for both the organization of the scientific program and for the logistics of the Workshop.
- Chairman of the Workshop: "Transversity 2008 - 2nd Workshop on Transverse Polarization Phenomena" - Ferrara, 28 to 31 May 2008 (http://www.fe.infn.it/transversity2008/)
Transversity and transverse spin of the proton are among the most important topics in the field of hadronic physics. The workshop was organized within the project PRIN 2006 and followd the one organized in Como in 2005. The workshop brought together both theoretical and experimental physicists involved in the study of the transverse structure of the nucleon, to exchange ideas and updates on the latest experimental data on the subject. As chair Paolo Lenisa was responsible for both the organization of the scientific program and for the logistics of the workshop which was attended by eighty physicists from around the world. The use of funds from the Virtual Institute for QCD VI-QCD, of which Paolo Lenisa is local manager, was used to finance the participation to the Workshop of nearly a dozen Italian and foreign students.
P. Lenisa is co-editor of the Proceedings of the Workshop (G. Ciullo, M. Contalbrigo, D. Hasch and P. Lenisa: Proceedings of "Transversity 2008 - 2nd Workshop on Transverse Polarization Phenomena" World Scientific - 2009)
- Chairman of the Workshop: PST2009 - XIII International Workshop on Polarized Sources, Targets and Polarimetry - Ferrara, 07 - 11 September 2009 (http://web.fe.infn.it/PST2009/)
Paolo Lenisa organized as Chairman the Workshop PST2009 - XIII International Workshop on Polarized Sources, Targets and Polarimetry held in Ferrara from 7 to 11 September 2009. The International Workshop organized on a biennial basis, aims at gathering together world experts in the technology of polarized beams and targets and related polarimetry. The nomination and subsequent selection of Ferrara as the seat by the International Spin Physics Committee, is an international acknowledgment for the expertise gained in the polarization field by Paolo Lenisa and his group. The workshop served to provide a complete overview of the different types of targets and polarized beams adopted in hadronic physics, but also properly highlighting the potential applications in fields outside physics, as in medicine. Particular attention in the organization of the scientific program was the discussion time, with the aim of promoting the exchange of information between the various experiences. The use of funds of the Virtual Institute QCD (VI-QCD) of which Paolo Lenisa was responsible, allowed to contribute to the travel expenses of more than a dozen students. Overall, the workshop was attended by over eighty physicists from around the world. As Chairman. P. Lenisa was occupied by both the organization of the scientific program and the logistics.
Paolo Lenisa is Co-editor of the Proceedings of the Workshop, published by World Scientific (G. Ciullo, M. and P. Contalbrigo Lenisa Proceedings of PST2009 - XIII International Workshop on Polarized Sources, Targets and Polarimetry, "- World Scientific 2011)
- Co-organizer of the Workshop "STORI11, 8th International Conference on Nuclear Physics at Storage Rings", Frascati, Italy, 9-14 October 2011 (http://www.lnf.infn.it/conference/stori11/)
Paolo Lenisa was part of the organizing committee of STORI11, held in Frascati 9 to 14 October 2011. The purpose of the conference, organized every three years, is to provide a broad overview of various aspects of nuclear physics studied in storage rings. Paolo Lenisa was conviener of the session devoted to experiments and future facilities and is co-editor of the Proceedings of the Conference published electronically by Proceedings of Science (PoS).
- Co-chair of the International School Niccolo’ Cabeo – 2013: “Physics beyond the Standard Model: the Precision Frontier”, Ferrara, Italia, 20-24 may 2013 (http://www.fe.infn.it/cabeo_school/)
Paolo Lenisa is Co-chair of the International School Niccolo’ Cabeo – 2013: “Physics beyond the Standard Model: the Precision Frontier”, held in Ferrara, Italia, 20-24 may 2013.
It is nowdays well established that the Standard Model is not the ultimate theory of the basic consitutents of our universe and their interactions. The challenge of the present and future fundamental research is to investigate the limits of the Standard Model and establish the experimental basis for a new and more complete theory.
Complementary to the global and highly localized effort of high-energy exploration at CERN, a plethora of worldwide-spread small and middle scale experiments are exploiting precision measurements to seek for sign of physics not included in the Standard Model.
The School addresses graduate students and young researchers and is meant to offer an overview of these experimental searches in the theoretical framework of present effective field theories. Program includes introductory lectures to quantum field theory and supersimmetry and dedicated experimental presentations on flavour physics and the search for EDM, antimatter, antigravity, dark-forces, gravitational waves.
PART IV: TEACHING ACTIVITY
Paolo Lenisa teaches the courses of General Physics I and II, recently joined in General Physics, for Faculty of Engineering, University of Ferrara since 2000. The courses are framed in the first year of the Degree in Engineering, and concern an average of 150 students per year. In the current structure, the course of General Physics is carried out in a period of three months and covers the topics of vector calculus, single particle dynamics, dynamics and statics of the rigid body and thermodynamics. The course consists of a total of 120 hours of front-lectures corresponding to 12 credits.
Particular importance for the management of courses, in compatible way with his research activity, has covered the intensive mode of carrying them out, which allows the compaction in periods of two/three months. Also the adoption of partial tests dedicated to the various topics covered in the course played also an important role in this sense, besides being highly appreciated by the students.
The popularity of the teaching of Paolo Lenisa by students is reflected by the evaluation questionnaires of the students who put his Course of General Physics as the most popular of the entire degree course in the last two academic years (questionnaires are publicly available from the website University of Ferrara).
To manage the contact with the students in an appropriate manner even during periods of absence from the office, great importance has played the introduction of a website dedicated to the course, which in the course of the last year came to a total of approximately 100,000 contacts in 10 years ( http://www.fe.infn.it/ lenisa ~ /). The website collects some applets to supplement the course topics and exercises done in class.
In parallel to the teaching activities related to the described courses, Paolo Lenisa carried out supervision and mentoring for thesis and PhD in supporting activities carried out within the research of HERMES Collaboration before, and PAX later. In particular Paolo Lenisa has been supervisor of doctoral thesis 5 and 8 thesis in physics at the University of Ferrara.
CHRONOLOGY
- Academic Year 1998 - 1999
Exercises performed in the course in General Physics II Degree in Civil Engineering, Faculty of Engineering, University of Ferrara.
Tutor of the Diploma thesis in Physics for the student David Reggiani, Faculty of Sciences, University of Ferrara entitled: "Study and Application of a Transversely Polarized Target for the HERMES experiment at HERA"
- Academic Year 1999 - 2000
Course of General Physics II Degree in Civil Engineering, Faculty of Engineering, University of Ferrara
Tutor of the Diploma thesis in Physics for the student Severino Tessarin, Faculty of Sciences, University of Ferrara, entitled "Determination of the accuracy of the measurement bias for the target experiment HERMES"
- Academic Year 2000 - 2001
Course of General Physics II Degree in Civil Engineering, Faculty of Engineering, University of Ferrara.
- Academic Year 2001 – 2002
Course of General Physics I Degree in Civil Engineering, Faculty of Engineering, University of Ferrara.
- Academic Year 2002 - 2003
Course of General Physics I Degree in Civil Engineering, Faculty of Engineering, University of Ferrara.
Supervisor for PhD in Physics at University of Ferrara for the student D. Reggiani. Title of the thesis "Precision Measurement of the Polarization of the HERMES Target"
- Academic Year 2003 - 2004
Course of General Physics I Degree in Civil Engineering, Faculty of Engineering, University of Ferrara.
- Academic Year 2004 - 2005
Course of General Physics I Degree in Civil Engineering, Faculty of Engineering, University of Ferrara.
Series of two lectures given at XV Study Days on Detectors, Turin Villa Gualino, 1:02:05 to 4:02:05 entitled "Polarization Rings Collection."
- Academic Year 2005 - 2006
Course of General Physics I Degree in Civil Engineering, Faculty of Engineering, University of Ferrara.
Supervisor for thesis PhD in Physics for the University of Ferrara student M. Capiluppi. Thesis title: "First Measurement of the Spin-Exchange Collisions Cross Section in the Low Temperature Region"
- Academic Year 2006 - 2007
Course of General Physics I Degree in Civil Engineering, Faculty of Engineering, University of Ferrara.
- Academic Year 2007 - 2008
Course of General Physics I Degree in Civil Engineering, Faculty of Engineering, University of Ferrara.
Course of General Physics II Degree in Civil Engineering, Faculty of Engineering, University of Ferrara.
Tutor for Master thesis in Physics at the University of Ferrara for the student P. Benati. Thesis title: "Characterization of a new trigger board for spin-filtering experiments"
Tutor for Master thesis in Physics Thesis at the University of Ferrara for the student S. Bertelli. Thesis title: "Study of the rdeuteron-breakup reaction in spin-filtering experiments for the polarization of antiproton beams"
- Academic Year 2008 - 2009
Course of General Physics I Degree in Civil Engineering, Faculty of Engineering, University of Ferrara.
Course of General Physics II Degree in Civil Engineering, Faculty of Engineering, University of Ferrara.
- Supervisor of the doctoral thesis in physics at the University of Ferrara for the student L. Barion. Thesis title: "Internal polarized gas targets: systematic studies on intensity and correlated effects."
- Tutor for Master thesis in Physics at the University of Ferrara for the student G. Guidoboni. Thesis title: "Design of the interlock-system of a test bench for silicon detectors"
- Academic Year 2009 - 2010
Course of General Physics Degree in Civil Engineering, Faculty of Engineering, University of Ferrara.
Tutor for the Master thesis in Physics at the University of Ferrara for the student A. Lupato. Thesis title: "Development of atomic beam sources of hydrogen and deuterium gas at high intensity."
- Academic Year 2010 - 2011
Course of General Physics Degree in Civil Engineering, Faculty of Engineering, University of Ferrara.
- Academic Year 2011 - 2012
Course of General Physics Degree in Civil Engineering, Faculty of Engineering, University of Ferrara.
Tutor of the PhD thesis in Physics at the University of Ferrara for the student P. Benati. Thesis title: "Development of a new trigger system for spin-filtering studies".
Tutor for the PhD thesis in Physics at the University of Ferrara for student S. Bertelli. Thesis title: "Proton induced deuteron breakup reactions at COSY."
Tutor for the master thesis in Physics at the University of Ferrara's Student E. Dall'Occo. Title of the thesis:
Optical characterization of radiators for aerogel Cherenkov detectors"
Tutor for the master thesis in Physics at the University of Ferrara student A. Ferroni. Title of the thesis:
"Density measurement of a polarized target for the PAX-experiment"
PART V: PRESENTATIONS AT CONFERENCES, MEETINGS, SCHOOLS
1996
- VII International Conference on Accelerators Applications in Industry and Research,
Nov. 1996, Danton (Texas)
"New Techniques for Laser Cooling of an Ion Beam in a Storage Ring"
1997
- 3rd Euroconference on Atomphysic heavily charged with stored ions
Sept. 1997, Ferrara (Italy)
"White-light Laser Cooling at the TSR"
- 14th International Spin Physics Symposium (SPIN 2000)
Oct 16-21, 2000, Osaka (Japan)
"The HERMES Internal Polarized Hydrogen and Deuterium Target"
2001
- Deutsche Gesellschaft Physikalische Spring Meeting
March 19 to 23, 2001, Erlangen (Germany)
"Das HERMES Polariziertes HD Target" (in German)
- International Workshop on Polarized Sources and Targets (PST 01)
Sep 30 - Oct 4, 2001, Nashville - Indiana (USA)
"The Gaseous Polarized HD Target of the HERMES Experiment"
2002
- Summer School and Workshop on COSY Physics
Aug. 28 - Sept. 4, 2002, Jülich (Germany)
"Study of Heavy Meson Production with a Polarized Internal Gas Target at COSY"
- 15th International Spin Physics Symposium (SPIN02)
Sep 9-14, 2002, Brookhaven National Lab - NY (USA)
"New Precision Results on the Spin Structure Function G1D"
- 15th International Spin Physics Symposium (SPIN02)
Sep 9-14, 2002, Brookhaven National Lab - NY (USA)
"Nuclear Polarization of Hydrogen Atoms on recombined Drifilm"
2003
- Quarks in Hadrons and Nuclei II
Sep 15 - 20, 2003, Rothenfels Castle, Oberwoelz, (Austria)
"Transversity Measurements at HERMES"
- 10th International Workshop on Polarised Sources and Targets
Sep 22-26, 2003, Novosibirsk (Russian Federation)
"The HERMES transversely Polarized Hydrogen Target"
2004
- "Scientific Opportunities and Challenges - China and the International Facility at Darmstadt"
April 14-16, Beijng (China)
"PAX: Polarized Antiproton eXperiments"
- 1st Caucasian_German School and Workshop on Hadron Physics
Aug. 30-Sept. 4 2004, Tbilisi (Georgia)
"PAX (Polarized antiprotons eXperiments)"
- 16th International Spin Physics Symposium (SPIN04)
Oct 10 - 16, 2004, Trieste (Italy)
"The HERMES Polarized Hydrogen and Deuterium Gas Targets"
2005
- XV Study Days on the detectors,
February 1 to 4, 2005, Villa Gualino - Torino (Italy)
"Polarization Rings Collection."
- 13th International Workshop on Deep Inelastic Scattering and QCD (DIS 2005)
April 27 - May 1, 2005, Madison-Wisconsin (USA)
"Spin Physics with Polarized antiprotons at GSI"
- Partonic structure of hadrons (concepts and phenomenology)
May 9-14, 2005, Trento (Italy)
"Polarized Antiproton Experiments at GSI"
- 6th International Conference on Nuclear Physics at Storage Rings
23-26 May 2005, Bonn (Germany)
Presentation by invitation.
"The PAX Proposal: Physics with Polarized antiprotons at GSI"
- HiF05 - High Intensity Frontier Workshop
Presentation by invitation.
May 28 - Jun. 01, 2005, Elba Island (Italy)
"Physics with Polarized antiprotons"
- Hpc2005 - Workshop on Hadronic Physics at COSY
July 25-29, 2005, Bad Honnef (Germany)
"Proton Spin and Polarized antiprotons"
- XCI National Congress of the Italian Society of Physics
Sept. 26 - Oct. 1, 2005, Catania
Presentation by invitation:
"Physics with Polarized Antiprotons"
2006
- 14th International Workshop on Deep Inelastic Scattering and QCD (DIS 2006)
April 20 to 24, 2006 Tsukuba, Japan
"Polarized measurements at sea JPARC."
- Observables in Antiproton-Proton Interactions and Their relevance in QCD
July 3-8, 2006, Trento, Italy
"The PAX Project"
- 2nd Caucasian_German School and Workshop on Hadron Physics
Aug. 31-Sept. 8 2006, Tbilisi (Georgia)
Presentation by invitation:
"Spin-filtering experiments"
2007
- Workshop: "Hard QCD with antiprotons at GSI-FAIR"
July 16-28, 2007, Trento, Italy
Presentation by invitation:
"Polarization technology at FAIR."
- Workshop: "Polarized antiprotons: how?"
August 29-31, 2007, Daresbury (Liverpool), UK
Presentation by invitation:
"Spin-Polarized antiprotons and physics."
- 11th International Conference on Meson-Nucleon Physics and the Structure of the Nucleon (MENU 2007)
September, 10-14, 2007 FZJ-Jülich, Germany
Presentation by invitation:
"Toward polarized antiprotons at FAIR."
2008
- Workshop: "Nuclear Medium Effects on Quarks and Gluon Structure of Hadrons"
July 03-07, 2008, Trento, Italy
Presentation at the invitation
"FAIR and PAX."
2010
- Workshop on High-energy hadron physics with hadron beams
January 06-08, 2010, Tsukuba, Japan
Presentation by invitation:
"Structure Functions and Spin-physics at FAIR"
- Workshop on Studying the hadron structure in Drell-Yan reactions
April 26-27, 2010, CERN, Switzerland
Presentation by invitation:
"Future Drell-Yan experiments at FAIR"
- SPIN2010 - 19th International Spin Physics Symposium
September 27th - October 2nd 2010, Juelich, Germany
Presentation at the invitation
"Highlights of PST2009 Workshop on Polarized Sources, Targets and Polarimetry"
2011
- The Structure and Dynamics of Hadrons-XXXIX International Workshop on Gross Properties of Nuclei and Nuclear Excitations
Jaunuary 16th-22nd, 2011, Hirschegg, Kleinwalsertal, Austria
Presentation by invitation:
"Possible future experiments on Hadron Structure at FAIR"
- LEAP 2011 - 10th International Conference on Low Energy Antiproton Physics
April 27th - May 1st, 2011, Vancouver, Canada
Presentation by invitation:
"Perspectives for Polarized antiprotons"
- PSTP 2011 - XIV International Workshop on Polarized Sources, Targets and Polarimetry
September, 12th-16th St. Petersburg, Russia
Presentation by invitation:
"The road to Polarized antiprotons"
2012
- Spin-physics Workshop in Gatchina
June, 24th-27th, Gatchina, Russia
Presentation by invitation:
"Perspectives for Polarized antiprotons."
- 5th Georgian-German School and Workshop in Basic Science
August, 5th-11th, Tbilisi, Georgia
Presentation by invitation:
"Polarized antiprotons: why and how."
