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Prospects of Polarized Fixed Target Drell-Yan Experiments

Prospects of Polarized Fixed Target Drell-Yan Experiments. Ming X. Liu Los Alamos National Laboratory Key words: Transverse Single Spin Asymmetry (TSSA) Drell-Yan (DY). Outline. Physics Motivation Facilities and Experimental Challenges Fermilab Current E906 – unpolarized DY

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Prospects of Polarized Fixed Target Drell-Yan Experiments

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  1. Prospects of Polarized Fixed Target Drell-Yan Experiments Ming X. Liu Los Alamos National Laboratory Key words: Transverse Single Spin Asymmetry (TSSA) Drell-Yan (DY)

  2. Outline • Physics Motivation • Facilities and Experimental Challenges • Fermilab • Current E906 – unpolarized DY • Future Polarized DY possibility • RHIC • Current PHENIX/STAR • Future possibilities • Polarized targets • J-Lab/UVA/SLAC • Outlook Ming X. Liu SPIN2010

  3. The Drell-Yan Process Ming X. Liu SPIN2010

  4. Complimentality between DIS and Drell-Yan Drell-Yan DIS Polarized DIS Polarized DY NOT yet! McGaughey, Moss, Peng, Ann.Rev.Nucl. Part. Sci. 49 (1999) 217 Both DIS and Drell-Yan process are tools to probe the quark and antiquark structure in hadrons (factorization, universality) 4 Ming X. Liu SPIN2010

  5. Nucleon Structure @Leading Twist Collinear Approximation (I) Partonic interpretation of hard scatterings Universal functions Ming X. Liu SPIN2010

  6. Including kT … 5 more (II) No K┴ dependence K┴ - dependent T-even K┴ - dependent T-odd Ming X. Liu SPIN2010

  7. Transversity and TMDs can be probed via DY Ming X. Liu SPIN2010

  8. Color Flow in DY and DIS Collins ‘02 Twist-3: sign change from gluonic-pole in hard parts In the overlapped region – consistent description Ji, Qiu, Vogelsang, Yuan ‘06 Bacchetta, Boer, Diehl, Mulders ‘08 The sign change – a new fundamental test of color gauge formalism and factorization Ming X. Liu SPIN2010

  9. Sivers Asymmetries in SIDIS and DY “Transverse-Spin Drell-Yan Physics at RHIC” (http://spin.riken.bnl.gov/rsc/write-up/dy_final.pdf) • Important test at RHIC of recent fundamental QCD predictions for the Sivers effect, demonstrating… attractive vs repulsive color charge forces HERMES Sivers Amplitude 0.1 0.2 0.3 x Ming X. Liu SPIN2010 9

  10. Sivers Functions and DY TSSA Anselmino et al PRD 79 -54010(2009) Expected AN of DY based on global fit to DIS fit of HERMES and COMPASS Ming X. Liu SPIN2010

  11. A future challenge Beginning to be measured at RHIC Importance of DY TSSA • Test the fundamental prediction of sign change in DY TSSA compared to DIS based on our understanding of the origin of TSSA • Test of gauge formulism • Test of QCD factorization • Help to resolve the proton spin puzzle? • One expect the observation of Sivers Asymmetry signals the existence of partonic orbital angular momentum only ~30% of spin Ming X. Liu SPIN2010

  12. Proposed Future Polarized DY Exp’s Y. Goto 4/2010 CERN DY • Polarized DY Dimuon Exp. at Fermilab Main Injector: 120GeV • RHIC fixed target possibility: 250 GeV Ming X. Liu SPIN2010

  13. (I): E906 Drell-Yan Polarized DY possibility: Polarized targets Polarize the Main Injector Or both 120 GeV proton beam 4.9m XTarget XBeam Ming X. Liu SPIN2010

  14. Polarized DY @Fermilab after E906 ? • Transversely Polarized Targets • Sivers functions for quark and anti-quark • Test AN sign change • Polarized Main Injector (A. Krisch & W. Lorenzon) • Polarized MI beam intensity • 2.3x1012 p/pulse (w/ 2.8s/pulse) on E906 target, 51cm LH2 • Lumi=1x1036/cm2/s • Double spin asymmetry – possible • Pion beam DY • Polarized target • Precision measurement of u,d-quark Siverse function Ming X. Liu SPIN2010

  15. E906 Parameters @Fermilab • 4<M<8 GeV • P1,2 > 0, 5, 10, 20 GeV • N = 5.3, 4.7, 3.5, 1.6 M dimuons • 50M DY, m>2GeV, sqrt(s)= 15 GeV (L=900 fb-1 or 3.5x1016 pp) • Beam energy = 120GeV • Beam structure and profile: • 2x1012 protons/sec, for 5 sec/per min • Beam size: σx< 10mm and σy< 5mm, • Two years’ total = 7x1018, 15% efficiency • Magnet: 8.4 T*m • pT kick ~ 2.5GeV • Absorber: 15 λI, beam dump 30λI • Energy loss = 3.5GeV, E906 cut: p > 15GeV • Multiple scattering 170/p mr • Mass resolution = 240MeV @J/Psi • Targets: < 15% λI • 50.8cm liquid hydrogen and deuterium • 12C, 56Fe, W Muons: P1,2 > 0, 5, 10, 20 xF = xBeam - xTarget Ming X. Liu SPIN2010

  16. Anselmino et al PRD 79 -54010(2009) 120 GeV @Main Injector xBeam P>0 P>5 P>10 P>20 xTarget Ming X. Liu SPIN2010

  17. DY Requires High Density Polarized Targets • DY dimuon production cross section small - @120 GeV FixT (M>4) ~ 5 pb • Solid Targets: possible NDY ~ 106 in ~1year, M> 4GeV • Gas Targets: not likely for an experimental precision of ~1% Ming X. Liu SPIN2010

  18. D. Crabb MENU10 UVA/J-Lab/SLAC Polarized proton/deuteron target • Polarized NH3/ND3 targets • Dynamical Nuclear Polarization • Operate at 5 T and 1 K. Pol ~ B/T • Used with high beam intensities – up to ~100 nA • Large capacity pumps • Polarizations: • p > 90%, • d ~ 50% • Able to handle high luminosity • up to ~ 1035 (Hall C) ~ 1034 (Hall B) Ming X. Liu SPIN2010

  19. D. Crabb MENU2010 Major Polarized Target Systems Ming X. Liu SPIN2010

  20. D. Crabb MENU2010 Dynamic Nuclear Polarization Ming X. Liu SPIN2010

  21. A. Krisch Fermilab 8/2010 Ming X. Liu SPIN2010

  22. Expected DY AN Sensitivity @120 GeV. • Target • 6 cm NH3 • 1019 proton P(muon)>5 GeV Ming X. Liu SPIN2010

  23. BRAHMS PHENIX STAR (II): Polarized DY w/ Fixed Target @RHIC ? Polarized fixed target DY exp. with extracted polarized proton beams: Fixed Target DY Exp. @Beam Dump • High density LH2/LD2 target • High density polarized targets 3 Map out x-dep. - 250 GeV proton beams - Pol up to 70% Ming X. Liu SPIN2010 23

  24. Proton Efficiency: Collider vs Fixed Target Mode (RHIC for e.g.) Design value: 2x1011x100 = 2 x 1013 proton per store per ring Collision rate ~ 10 MHz • Num. of collisions per store • 10M x 3600sec x 8 hr = 2.9 x 1010 • Fract. of p’s used = 3 x1011 / 2 x 1013 = 1.5 x 10-2 In the fixed target mode, for a ~20% interaction length, we can use ~20% of the protons from the beam • 0.2/ 1.5 x 10-2 = 13x gain in luminosity Center of Mass Energies for p+p • Collider mode: sqrt(s) = 500 GeV • Fixted T mode: sqrt(s) = 22 GeV Ming X. Liu SPIN2010

  25. Fixed Target @RHIC ? • Beam dump experiment: dimuon channel • Parasitic mode • Significant beams still left at the end of a store (~50%) • Cycle time ~8hr • Dedicated fixed target • Cycle time ~ 1hr • Dimu x-section @ 250 GeV (M>4) ~20pb • Targets • E906-like unpolarized LH2 target • 51cm LH2 (2.1x1024/cm2) • Can handle L ~ 1x1036cm-2s-1 • Polarized solid target • UVA/J-Lab/SLAC: L ~1035cm-2s-1 • Advantages • Polarized beams • (polarized) targets • Higher Energy and large x-coverage • High luminosity Ming X. Liu SPIN2010

  26. 250 GeV Polarized Beam Fixed T.X-Coverage xBeam P>5GeV p>0 P>10GeV P>20GeV xTarget Ming X. Liu SPIN2010

  27. DY AN Sensitivity@250 GeV Fixed Target 4.5<M<8 GeV qT < 1 GeV 10 fb-1 50 fb-1 xF Ming X. Liu SPIN2010

  28. If Polarized Beam and Target … 1) Double-spin asymmetry (ALL) with longitudinally polarized beam/target in Drell-Yan probe quark helicity distributions 2) Double-spin asymmetry (ATT) with transversely polarized beam/target in Drell-Yan probe quark transversity distribution Ming X. Liu SPIN2010

  29. Summary and Outlook • Pol. DY TSSA provides unique opportunity to study QCD spin dynamics and nucleon structure • Experimental test of the sign change will provide a critical test of our understanding of the origin of TSSA in QCD and the factorization • Precision determination of the Sivers and other TMDs for both quark and anti-quark in a wide kinematic range. • Polarized fixed target DY experiments could be realized at, • Fermilab • RHIC (w/ polarized targets) • Collaboration: M.Bai, D. Crabb, J.Chen, Y. Goto, X.Jiang Pbeam=120 GeV Pbeam=250 GeV Kang & Qiu PRD 81 (2010) 054020 Ming X. Liu SPIN2010

  30. http://p25ext.lanl.gov/~ming/SantaFe-DY/Drell-Yan-Workshop.htmhttp://p25ext.lanl.gov/~ming/SantaFe-DY/Drell-Yan-Workshop.htm • Topics: - Pol. DY Physics - Pol. Beams - Pol. Targets Ming X. Liu SPIN2010

  31. Backup Ming X. Liu SPIN2010

  32. Polarized Solid Target • Maximum beam current – UVA/JLAB/SLAC target • Up to ~100nA = 6.2x1011p/s -> maximun lumi = 1035 • E906: 1x1013ppp (5 sec slow extraction, spill/min) =>320 nA (5sec avg), or 27nA(avg over 1 minute) =>L = 3.4 x 1035 cm-2s-1 • J-PARC: 5x1012ppp = 2.5x1012x2 sec per pulse • I= 403 nA (2 sec avg) • RHIC: 2x1011/bunch x 100 per store • 2x1013 pps (1 hr to fill, compared to 1x1013 ppp 1 min per spill at Fermilab) • A factor of 30 less than E906 in terms of total protons • Make it 100nA = 200/6.2=32 sec slow extraction • COMPASS NH3 target • Beam intensity up to 108/s, lumi = 1.7x1033 • Heat load ~2 mW • (refrigerator cooling power 5mW) • E906 unpolarized LH2 target • E906: 51cm long => ~5% interaction length • Target limit: L = 1x1036 cm-2s-1 , ~3 times of E906 beam luminosity Ming X. Liu SPIN2010

  33. Solid Target Mini Summary • Mature Technology • Being used in other areas, eg MRI Studies; 13C • Proton Polarizations > 90% • Deuteron Polarizations > 70% • Nuclear Polarizations eg 6Li ~ 60% • Material studies eg CH3 , CH4 (irradiation) • NMR improvements and modifications. Ming X. Liu SPIN2010

  34. Meson East Spectrometer (E605/772/789/866) Open-aperture Closed-aperture Beam-dump (Cu) J/Ψ J/Ψ Ψ’ σ(J/ψ) ~ 150 MeV σ(J/ψ) ~ 300 MeV σ(J/ψ) ~ 15 MeV Ming X. Liu SPIN2010

  35. Ming X. Liu SPIN2010

  36. Hall A polarized 3He target J. Chen • Both longitudinal, transverse and vertical • Luminosity=1036 (1/s) (highest in the world) • High in-beam polarization ~ 65% • Effective polarized neutron target • 9 completed experiments 4 are currently running 6 approved with 12 GeV (A/C) Ming X. Liu SPIN2010

  37. Theoretical Predictions for DY in pp Kang & Qiu PRD 81 (2010) 054020 Twist-3 Anselmino, et al PRD 79 (2009) 054010 TMD Fixed Target: p=250 GeV Kang & Qiu PRD 81 (2010) 054020 Ming X. Liu SPIN2010 37

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