Lenisa

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dr. Paolo Lenisa Università di Ferrara and INFN - ITALY ECT – Workshop: Hadronic structure of the nucleon Trento, May 9-13 http://www.fz-juelich.de/ikp/pax

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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 PAX Collaboration Spokespersons: Paolo Lenisa lenisa@mail.desy.de Frank Rathmann f.rathmann@fz-juelich.de

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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) PAX Collaboration

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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 15.09.04 F. Rathmann et al., A Method to polarize stored antiprotons to a high degree (Phys. Rev. Lett. 94, 014801 (2005)) 15.01.05 Technical Report submitted 14-16.03.05 QCD-PAC meeting at GSI Polarization enters in the core of FAIR

Outline: 

Outline WHY? Physics Case HOW? Polarized Antiprotons WHAT? Staging Detector and signal estimate WHERE AND WHEN? The FAIR project at GSI PAX: Polarized Antiproton Experiments

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Physic Topics Transversity Electromagnetic Form Factors Hard Scattering Effects SSA in DY, origin of Sivers function Soft Scattering Low-t Physics Total Cross Section pbar-p interaction Physics Polarization Staging Signals FAIR

Physics Case: Central Physics Issue: 

Physics Case: Central Physics Issue Transversity distribution of the nucleon: last leading-twist missing piece of the QCD description of the partonic structure of the nucleon directly accessible uniquely via the double transverse spin asymmetry ATT in the Drell-Yan production of lepton pairs theoretical expectations for ATT in DY > 0.2 transversely polarized antiprotons transversely polarized proton target definitive observation of h1q (x,Q2) of the proton for the valence quarks Physics Polarization Staging Signals FAIR

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Transversity Physics Polarization Staging Signals FAIR

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Transversity in Drell-Yan processes p p QL Q l+ l- Q2=M2 QT Polarized Antiproton Beam → Polarized Proton Target (both transversely polarized) Physics Polarization Staging Signals FAIR

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PAX: s~30-210 GeV2, M2~10-100 GeV2, τ=x1x2=M2/s~0.05-0.6 → Exploration of valence quarks (h1q(x,Q2) large) ATT for PAX kinematic conditions Physics Polarization Staging Signals FAIR A. Efremov et al. Eur. Phys. J. C 35 (2004) 207

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Energy for Drell-Yan processes “safe region”: M≥MJ/Y t ≥ M2J/Y/s QCD corrections at smaller M? H. Schimizu, G. Sterman, W. Vogelsang and H. Yokoya, hep-ph/0503270 V. Barone et al., in preparation Physics Polarization Staging Signals FAIR

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NLO corrections: cross section Physics Polarization Staging Signals FAIR

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NLO corrections: ATT Physics Polarization Staging Signals FAIR

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Measure ATT also in J/Y resonance region M. Anselmino, V. Barone, A. Drago, N. Nikolaev Physics Polarization Staging Signals FAIR Resonance region

Proton Electromagnetic Formfactors : 

Proton Electromagnetic Formfactors Measurement of relative phases of magnetic and electric FF in the time-like region Possible only via SSA in the annihilation pp → e+e- Double-spin asymmetry independent GE-Gm separation test of Rosenbluth separation in the time-like region S. Brodsky et al., Phys. Rev. D69 (2004) Physics Polarization Staging Signals FAIR

Study onset of Perturbative QCD: 

p (GeV/c) Study onset of Perturbative QCD Pure Meson Land Meson exchange ∆ excitation NN potential models Transition Region Uncharted Territory Huge Spin-Effects in pp elastic scattering large t: non-and perturbative QCD High Energy small t: Reggeon Exchange large t: perturbative QCD Physics Polarization Staging Signals FAIR

pp Elastic Scattering from ZGS: 

pp Elastic Scattering from ZGS Spin-dependence at large-P (90°cm): Hard scattering takes place only with spins . D.G. Crabb et al., PRL 41, 1257 (1978) T=10.85 GeV Similar studies in pp elastic scattering Physics Polarization Staging Signals FAIR

Outline: 

Outline WHY? Physics Case HOW? Polarized Antiprotons WHAT? Staging Detector and signal estimate WHERE AND WHEN? The FAIR project at GSI (D) PAX: Polarized Antiproton Experiments

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Polarized internal target Physics Polarization Staging Signals FAIR

The HERMES target: 

The HERMES target Physics Polarization Staging Signals FAIR

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The HERMES target Pz+ = |1> + |4> Pz- = |2> + |3> Physics Polarization Staging Signals FAIR

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The HERMES target Physics Polarization Staging Signals FAIR

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The HERMES target Physics Polarization Staging Signals FAIR

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Performance of Polarized Internal Targets Transverse Field (B=297 mT) HERMES: Stored Positrons PINTEX: Stored Protons Targets work very reliably (months of stable operation) Physics Polarization Staging Signals FAIR

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Principle of spin filter method Physics Polarization Staging Signals FAIR

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Principle of spin filter method Polarized H target Physics Polarization Staging Signals FAIR

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Principle of spin filter method For low energy pp scattering: 1<0  tot+<tot- Physics Polarization Staging Signals FAIR

Experimental Setup at TSR (1992): 

Experimental Setup at TSR (1992) Physics Polarization Staging Signals FAIR

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1992 Filter Test at TSR with protons Experimental Setup Results F. Rathmann. et al., PRL 71, 1379 (1993) T=23 MeV Physics Polarization Staging Signals FAIR

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Puzzle from FILTEX Test Observed polarization build-up: dP/dt = ± (1.24 ± 0.06) x 10-2 h-1 Expected build-up: P(t)=tanh(t/τpol), 1/τpol=σ1Qdtf=2.4x10-2 h-1  about factor 2 larger! σ1 = 122 mb (pp phase shifts) Q = 0.83 ± 0.03 dt = (5.6 ± 0.3) x 1013cm-2 f = 1.177 MHz Three distinct effects: Selective removal through scattering beyond Ψacc=4.4 mrad σR=83 mb Small angle scattering of target protons into ring acceptance σS=52 mb Spin transfer from polarized electrons of the target atoms to the stored protons σEM=70 mb (-) Horowitz & Meyer, PRL 72, 3981 (1994) H.O. Meyer, PRE 50, 1485 (1994)

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Spin transfer from electrons to protons Polarization Staging Signals Timeline

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Spin Transfer Cross Section Physics Polarization Staging Signals FAIR

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Beam lifetimes in the APR Physics Polarization Staging Signals FAIR

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Polarization Buildup: optimal polarization time Physics Polarization Staging Signals FAIR

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Optimum Beam Energies for Buildup in APR F. Rathmann et al., Phys. Rev. Lett. 94, 014801 (2005) Physics Polarization Staging Signals FAIR

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Filter Test: T = 23 MeV Ψacc= 4.4 mrad Beam Polarization Physics Polarization Staging Signals FAIR

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Antiproton Polarizer Ring (APR) Physics Polarization Staging Signals FAIR

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Spin-filtering with hadronic interaction Model A: T. Hippchen et al. Phys. Rev. C 44, 1323 (1991) P Kinetic energy (MeV) Physics Polarization Staging Signals FAIR

Outline: 

Outline WHY? Physics Case HOW? Polarized Antiprotons WHAT? Staging Detector and signal estimate WHERE AND WHEN? The FAIR project at GSI (D) PAX: Polarized Antiproton Experiments

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Staging: Phase I (PAX@CSR) Physics: EMFF pbar-p elastic Experiment: pol./unpol. Pbar (3.5 GeV/c) on int. pol. target Independent from HESR running Physics Polarization Staging Signals FAIR

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Staging: Phase II (PAX@HESR) 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. Physics: Transversity Second IP with minor interference with PANDA Physics Polarization Staging Signals FAIR

Outline: 

Outline WHY? Physics Case HOW? Polarized Antiprotons WHAT? Staging Detector and signal estimate WHERE AND WHEN? The FAIR project at GSI (D) PAX: Polarized Antiproton Experiments

Kinematics and cross section: 

Kinematics and cross section M2 = s x1x2 xF=2QL/√s = x1-x2 Estimated luminosities: Fixed target: 2.7x1031 cm-2s-1 Collider: 1-2 x 1030 cm-2s-1 Physics Polarization Staging Signals FAIR

ATT asymmetry: angular distribution: 

ATT asymmetry: angular distribution Needs a large acceptance detector (LAD) Asymmetry is largest for angles =90° Asymmetry varies like cos(2f). Physics Polarization Staging Signals FAIR

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Designed for Collider but compatible with fixed target Cerenkov (200 mm) (20 mm) GEANT simulation PAX detector concept Physics Polarization Staging Signals FAIR

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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 Physics Polarization Staging Signals FAIR

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Npbar = 1x1011 f=LCSR/bc dt=1x1014cm-2 Q=0.8 (p pol) P=0.3 (pbar pol) e=0.5 Estimated signal for EMFF (Phase I) PS170 and E835 PAX could run down to 200 MeV/c with double polarization Running days to get DO = 0.05 Polarization Staging Signals Timeline

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BNL E838 Estimated Signal for pbar p elastic (Phase I) Cross section estimation for p=3.6 GeV/c, q=120° Event rate (Dt=0.1 GeV2): 2 hours to get N10 Polarization Staging Signals Timeline

PAX Integrated Luminosities for Physics Cases: 

PAX Integrated Luminosities for Physics Cases pb-1 fb-1 Integrated Luminosity EMFF, DSA, s=3.76 GeV2 ppbar elastic, DSA, t=4 GeV2 Phase-I: L=1.5·1031 cm-2s-1 Antiproton Beam Polarization Ppbar=0.3, Proton Polarization Pp=0.8 Phase-II: L=2·1030 cm-2s-1 EMFF, DSA, s=9 GeV2 Absolute Error ΔDSA=0.05 h1, DSA, M>2 GeV, Δ=10% h1, DSA, M>4 GeV, Δ=20% (1 y) (4 y) (1 y)

Outline: 

Outline WHY? Physics Case HOW? Polarized Antiprotons WHAT? Staging Detector and signal estimate WHERE AND WHEN? The FAIR project at GSI (D) PAX: Polarized Antiproton Experiments

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Faciltiy for Antiproton and Ion Research (GSI, Darmstadt, Germany) Proton linac (injector) 2 synchrotons (30 GeV p) A number of storage rings  Parallel beams operation Physics Polarization Staging Signals FAIR

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FLAIR: (Facility for very Low energy Anti-protons and fully stripped Ions) SIS100/300 HESR: High Energy Storage Ring: PANDA and PAX NESR CR-Complex The FAIR project at GSI 50 MeV Proton Linac Physics Polarization Staging Signals FAIR

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Phase 0: 2005-2012 Polarization tests, polarizer design and construction. Phase I: 2013-2017 APR+CSR @ GSI Physics: EMFF with fixed target Phase II: 2018 - … HESR+CSR asymmetric collider Physics: h1 Timeline Physics Polarization Staging Signals FAIR

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Conclusions Challenging opportunities accessible with polarized pbar. Unique access to a wealth of new fundamental physics observables Central physics issue: h1q (x,Q2) of the proton in DY processes Other issues: Electromagnetic Formfactors Polarization effects in Hard and Soft Scattering processes differential cross sections, analyzing powers, spin correlation parameters Staging approach Projections for double polarization experiment (tests) : Pbeam > 0.30 L> 1.6 ·1030 cm-2s-1 (Collider), L 2.7 ·1031 cm-2s-1(fixed target) Detector concept: Large acceptance detector with a toroidal magnet

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