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Transversity and the PAX collaboration @ GSI Alessandro Drago University of Ferrara

Transversity and the PAX collaboration @ GSI Alessandro Drago University of Ferrara. About the PAX proposal for the new GSI Transversity distribution direct access to h 1 via A TT Sivers distribution testing: (Sivers) DY = - (Sivers) DIS. PAX Collaboration. Spokespersons:

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Transversity and the PAX collaboration @ GSI Alessandro Drago University of Ferrara

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  1. Transversityand the PAX collaboration @ GSIAlessandro DragoUniversity of Ferrara

  2. About the PAX proposal for the new GSI • Transversity distribution direct access to h1 via ATT • Sivers distribution testing: (Sivers)DY = - (Sivers)DIS

  3. PAX Collaboration Spokespersons: Paolo Lenisa lenisa@mail.desy.de Frank Rathmann f.rathmann@fz-juelich.de Yerevan Physics Institute, Yerevan, Armenia Department of Subatomic and Radiation Physics, University of Gent, Belgium University of Science & Technology of China, Beijing, P.R. China Department of Physics, Beijing, P.R. China Palaiseau, Ecole Polytechnique Centre de Physique Theorique, France High Energy Physics Institute, Tbilisi State University, Tbilisi, Georgia Nuclear Physics Department, Tbilisi State University, Georgia Forschungszentrum Jülich, Institut für Kernphysik Jülich, Germany Institut für Theoretische Physik II, Ruhr Universität Bochum, Germany Helmholtz-Institut für Strahlen- und Kernphysik, Bonn, Germany Physikalisches Institut, Universität Erlangen-Nürnberg, Germany Langenbernsodorf, UGS, Gelinde Schulteis and Partner GbR,Germany Department of Mathematics, University of Dublin,Dublin, Ireland Università del Piemonte Orientale and INFN,Alessandria,Italy Dipartimento di Fisica dell’Università and INFN, Cagliari, Italy Università dell’Insubria and INFN,Como,Italy Instituto Nationale di Fisica Nuclelare, Ferrara, Italy

  4. PAX Collaboration Dipartimento di Fisica Teorica, Universita di Torino and INFN, Torino, Italy Instituto Nationale di Fisica Nucleare, Frascati, Italy Andrej Sultan Institute for Nuclear Studies, Dep. of Nuclear Reactions, Warsaw, Poland Petersburg Nuclear Physics Institute, Gatchina, Russia Institute for Theoretical and Experimental Physics, Moscow, Russia Lebedev Physical Institute, Moscow, Russia Physics Department, Moscow Engineering Physics Institute, Moscow, Russia Laboratory of Theoretical Physics, Joint Institute for Nueclear Research, Dubna, Russia Laboratory of Particle Physics, Joint Institute for Nuclear Research, Dubna, Russia Laboratory of Nuclear Problems, Joint Institute for Nuclear Research, Dubna, Russia Budker Institute of Nuclear Physics, Novosibirsk, Russia High Energy Physics Institute, Protvino, Russia Institute of Experimental Physics, Slovak Academy of Science, Kosice Slovakia Department of Radiation Sciences, Nuclear Physics Division, Uppsala University, Uppsala, Sweden Collider Accelerator Department, Brookhaven National Laboratory, Broohhaven USA RIKEN BNL Research Center Brookhaven National Laboratory, Brookhaven, USA University of Wisconsin, Madison, USA Department of Physics, University of Virginia, USA 178 physicists 35 institutions (15 EU, 20 NON-EU)

  5. The PAX proposal Jan. 04 LOI submitted 15.06.04 QCD PAC meeting at GSI 18-19.08.04 Workshop on polarized antiprotons at GSI 15.01.05Technical Report submitted 14-16.03.05 QCD-PAC meeting at GSI Polarization enters in the core of FAIR

  6. Principle of spin filter method P beam polarization Q target polarization k || beam direction σtot = σ0 + σ·P·Q + σ||·(P·k)(Q·k) For initially equally populated spin states:  (m=+½) and  (m=-½) transverse case: longitudinal case: Unpolarized anti-p beam Polarized H target

  7. Principle of spin filter method P beam polarization Q target polarization k || beam direction Polarized anti-p beam σtot = σ0 + σ·P·Q + σ||·(P·k)(Q·k) For initially equally populated spin states:  (m=+½) and  (m=-½) transverse case: longitudinal case: Unpolarized anti-p beam Polarized H target

  8. Meyer PRE 50 (1994) 1485Rathmann et al. PRL 71(1993)1379

  9. Polarization with hadronic pbar-p interaction Model D: V. Mull, K. Holinde, Phys. Rev. C 51, 2360 (1995) P 0.20 0.20 0.15 0.15 0.10 0.10 0.05 0.05 1 1 10 10 1000 1000 100 100 Kinetic energy (MeV) Model A: T. Hippchen et al. Phys. Rev. C 44, 1323 (1991) P Kinetic energy (MeV)

  10. Ψacc=50 mrad EM only 0.4 40 30 0.3 20 Beam Polarization P(2·τbeam) 10 0.2 5 0.1 0 1 10 100 T (MeV) Beam Polarization Filter Test: T = 23 MeV Ψacc= 4.4 mrad

  11. Staging: Phase I (PAX@CSR) Physics: EMFF pbar-p elastic Experiment: pol./unpol. pbar on internal polarized target Independent from HESR running

  12. Staging: Phase II (PAX@HESR) Physics: Transversity EXPERIMENT: 1. Asymmetric collider: polarized antiprotons in HESR (p=15 GeV/c) polarized protons in CSR (p=3.5 GeV/c) 2. Internal polarized target with 22 GeV/c polarized antiproton beam.

  13. PAX:Polarizedantiproton beam → polarizedproton target (both transverse) l+ q2=M2 l- q qT p p qL M invariant Mass of lepton pair Transversity in Drell-Yan processes

  14. ATT for PAX kinematic conditions ATT/aTT > 0.2 Models predict |h1u|>>|h1d| RHIC: τ=x1x2=M2/s~10-3 → Exploration of the sea quark content(polarizations small!) ATT very small (~ 1 %) PAX: M2~10-100 GeV2, s~45-200 GeV2, τ=x1x2=M2/s~0.05-0.6 →Exploration ofvalence quarks(h1q(x,Q2) large)

  15. 2 k events/day collider 22 GeV M (GeV/c2) Kinematics and cross section • M2 = s x1x2 • xF=2QL/√s = x1-x2

  16. Energy for Drell-Yan processes "safe region": QCD corrections might be very large at smaller values of M: yes, for cross-sections, not for ATT K-factor almost spin-independent Fermilab E866 800 GeV/c H. Shimizu, G. Sterman, W. Vogelsang and H. Yokoya, hep-ph/0503270

  17. s=30 GeV2 s=45 GeV2 s=210 GeV2 s=900 GeV2

  18. l+ l+ q q J/ψ l– l– q q all vector couplings, same spinor structure and, at large x1, x2 measure ATTalsoin J/ψ resonance region Mauro Anselmino, V. Barone, A. D. and N. Nikolaev PLB 594 (2004) 97

  19. Estimated signal for h1 (phase II) 1 year of data taking Collider: L=2x1030 cm-2s-1 Fixed target: L=2.7x1031 cm-2s-1

  20. Transversity in various quark models MIT CDM CQSM g1 evol

  21. Measuring the Sivers function Direct access to Sivers function Sivers function usual parton distribution test QCD basic result: J. Collins process dominated byno Collins contribution usual fragmentation function same process at RHIC is dominated by Sivers function non-vanishing in gauge theories. Chiral models with vector mesons as gauge bosons can be used A.D. PRD71(2005)057501. (Sivers)u = -(Sivers)d in chiral models at leading order in 1/Nc .

  22. Conclusions • PAX Collaboration proposal @ GSI: First experiment with a polarized antiproton beam • Possibility of measuring h1 in the valence region • Possibility of testing the gauge-theory dictated rule (Sivers)DY = - (Sivers)DIS

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