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Transverse Spin Physics @RHIC the present and future

Transverse Spin Physics @RHIC the present and future. Ming X. Liu Los Alamos National Lab. Absolute Polarimeter (H jet). Highest Energy Polarized Proton Collider @RHIC. RHIC pC Polarimeters. Siberian Snakes. P HOBOS. B RAHMS. Siberian Snakes. Spin Flipper. S TAR & pp2pp. P HENIX.

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Transverse Spin Physics @RHIC the present and future

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  1. Transverse Spin Physics @RHICthe present and future Ming X. Liu Los Alamos National Lab

  2. Absolute Polarimeter (H jet) Highest Energy Polarized Proton Collider @RHIC RHIC pC Polarimeters Siberian Snakes PHOBOS BRAHMS Siberian Snakes Spin Flipper STAR & pp2pp PHENIX Spin Rotators Partial Snake Energy: up to 500GeV Pol: 70% Helical Partial Snake Strong Snake Polarized Source LINAC AGS BOOSTER 200 MeV Polarimeter Rf Dipole AGS Internal Polarimeter AGS pC Polarimeter Duke Spin Workshop Ming Liu

  3. Duke Spin Workshop Ming Liu

  4. Transverse Physics with PHENIX Detector Central spectrometers Track charged particles and detect electromagnetic processes Forward muon spectrometers Identify and track muons Forward calorimeters Measure forward photon Pions, eta, gamma … Relative Luminosity Beam-Beam Counter (BBC) Zero-Degree Calorimeter (ZDC) Duke Spin Workshop Ming Liu

  5. STAR Experiment New for Run 8: FMS • Stack of 1264 lead glass cells, roughly 18 X0 in z. • Located at far West side of Hall, at the opening to RHIC tunnel. Faces blue beam. • 7.5 meters from interaction point East FPD (since runs 3) Duke Spin Workshop Ming Liu

  6. The Present and the Challenges • Single inclusive particle AN • Pions, Etas and Kaons (BRAHMS, PHENIX, STAR) • Leading neutrons (PHENIX) • Heavy quarks (PHENIX) • Correlation measurements • Di-jets (STAR) • Two-particles (PHENIX) Duke Spin Workshop Ming Liu

  7. RHIC 20,000 GeV beam Transverse SSA’s from polarized proton beams from low to high energies FNAL 200 GeV beam AGS 22 GeV beam ZGS 12 GeV beam PRL (2004) PLB261, 201 (1991) PLB264, 462 (1991) PRD65, 092008 (2002) PRL36, 929 (1976) Perturbative cross section Non-Perturbative cross section Duke Spin Workshop Ming Liu

  8. p p 200 GeV 62.4 GeV Note different scales K K K- asymmetries underpredicted 200 GeV 62.4 GeV p p Large antiproton asymmetry?? Unfortunately no 62.4 GeV measurement 200 GeV 62.4 GeV Duke Spin Workshop Ming Liu

  9. Forward 0 Single Spin Asymmetry(SSA) At √s=200GeV, 0 cross-section measured by STAR FPD is consistent with the NLO pQCD calculation. Results at <>=3.3 and <>=3.8 have been included in the DSS global pion fragmentation function analysis. (Phys.Rev.D75(2007) 114010) Phys.Rev.Lett.101:222001,2008 9 Duke Spin Workshop Ming Liu From Spin2008 talk by J.Drachenberg, arXiv:0901.2763

  10. STAR pT Dependence of AN For Fixed XF, the asymmetry AN does not fall with pT as predicted by models and perhaps expected on very general grounds. • NLO PQCD does describe the size and shape of this • forward p0 cross section. • Model calculations (Sivers, • Collins or twist-3) can explain the XF dependence of AN. • X Flat or increasing dependence • of AN on pTis very difficult • to understand within any of • these frameworks! Phys.Rev.Lett.101:222001,2008 Duke Spin Workshop Ming Liu

  11. Preliminary Run8 FMS π0 AN AN vs. xF  Consistent with previous measurements STAR Preliminary Duke Spin Workshop Ming Liu From SPIN08 talk by N. Poljack, arXiv:0901.2828

  12. For , the asymmetry in the Eta mass region is greater than 5 sigma above zero, and about 4 sigma above the asymmetry in the p0 mass region. WWND10 Eun AN in p0 and Eta Mass Regions • Nphoton = 2 • Center Cut (h and f) • Pi0 or Eta mass cuts • Zgg < 0.85 • Average Yellow Beam Polarization = 56% Duke Spin Workshop Ming Liu

  13. Forward Pion / Eta Production with High Energy Polarized Proton / Antiproton Beams WWND10 Eun Duke Spin Workshop Ming Liu

  14. New Channels: Heavy Quark • D meson AN • Production dominated by gluon-gluon fusion at RHIC energy • Gluon transversity zeroAsymmetry cannot originate from Transversity x Collins • Sensitive to gluon Sivers effect (poorly constrained by pol DIS) Theoretical prediction: p↑pDX Anselmino et al, Phys. Rev. D 70, 074025 (2004) Duke Spin Workshop Ming Liu

  15. Latest Results of Heavy Quark SSAProbing Gluon’s Sivers Asymmetry First measurement of AN in heavy vector meson J/Psi production Motivated new theoretical study Constrains on gluons Sivers function. Led to a new development in spin physics, beyond traditional spin topics, study J/Psi production mechanisms. (F. Yuan 08) D->μ- J/Psi • Gluon’s Sivers fun was not constrained well by DIS data • PHENIX Charm data exclude the maximum gluon Sivers Fun (Anselmino et al, 06) • Much improved results expected soon (Run6+Run8) Duke Spin Workshop Ming Liu

  16. neutron Forward Neutrons at Ös=200 GeV Duke Spin Workshop Ming Liu

  17. The Future Opportunity • Single inclusive particles • Pions, Eta and Kaons (PHENIX, STAR) • Heavy Quarks (PHENIX) • Drell-Yan, W/Z (PHENIX, STAR) • Correlations • Di-jets (STAR) • Two-particles (PHENIX) • Direct-photon + Jet (PHENIX, STAR) Duke Spin Workshop Ming Liu

  18. Future Opportunity Vertex Detectors (2011-2012) Large acceptance precision tracking Drell-Yan Heavy quarks Jets Forward Calorimeter(2012-2013) Proposed PHENIX Upgrade ( 1 < eta < 3 ) AN 0, Direct γ, γ-Jet Collins-type measurements Duke Spin Workshop Ming Liu

  19. Attractive vs Repulsive “Sivers” Effects Unique Prediction of Gauge Theory ! DIS: attractive Drell-Yan: repulsive Duke Spin Workshop Ming Liu

  20. Transverse Spin Physics ~2015: AN (Drell-Yan ->μ+μ-) “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 Duke Spin Workshop Ming Liu

  21. Drell Yan charm beauty Drell Yan combinatorial background ϒ-states J/Ψ charm beauty • DY: 4 GeV < M < 9 GeV; B-background: use FVTX SVTX Heavy Quark and Drell-Yan • Tracking muons with MuTr+FVTX • Prompt muons from DY • Displaced tracks from π/K and heavy quark decays DCA < 1 σ cut: Increase DY/bb ~ 5 Duke Spin Workshop Ming Liu

  22. Transverse Spin Physics (cont.)A unique opportunity @RHIC to study charm physics! Kang, Qiu, Yuan, Vogelsang, Phys. Rev. D 78,114013(2008) Duke Spin Workshop Ming Liu

  23. Transverse Physics W+/- & Z0 SSA @500GeV ? Kang & Qiu PRL 103, 172001 (2009) • Latest theoretical progress • Test time-reversal universality of Sivers functions with W/Z • Expect large asymmetry (from DIS fit) • Flavor-identified Sivers Funs • Expected Statistics @1fb-1 500GeV • W+/- μ+/- ~20K • Z0 -> μ+μ- ~ 1K W+/- Z0 Kang & Qiu arX 0912.1319 Duke Spin Workshop Ming Liu 23

  24. M. Ansilmino PHENIX Spinfest 2008 Outlook “Polarization data has often been the graveyard of fashionable theories. If theorists had their way, they might just ban such measurements altogether out of self-protection.” J.D. Bjorken NATO Advanced Research Workshop on QCD Hard Hadronic Processes St. Croix, 1987 Duke Spin Workshop Ming Liu 24

  25. Duke Spin Workshop Ming Liu

  26. Renaissance of Transverse Spin Physics • Recent experimental observation of non-Zero Sivers and Collins effects • HERMES, 05,09; COMPASS, 05,09 ; BELLE 06 • Very active/rapid theoretical progress • Spin-dependent TMD • Sivers 90; Colllins 93; Brodsky-Hwang-Schmidt, 02 • Twist-3 quark-gluon correlations (coll.) in DIS • Efremov-Teryaev, 82, 84; Qiu-Sterman, 91,98 • Twist-3 tri-gluon correlations in p+p • Kang-Qiu-Vogelsang-Yuan 08 • Unified picture of TMD and Twist-3 • Ji-Qiu-Vogelsang-Yuan 06; Yuan-Zhou, 09 • Opportunity for new study of QCD dynamics • Sivers Funs in DIS & DY • Flavor Dep. Sivers Fun & OAM • quark-gluon and tri-gluon correlation • Future direction @RHIC-SPIN? • Large SSA observed at forward rapidity @RHIC • Open charm and beauty • Drell-Yan and Vector mesons • Light hadrons at forward rapidity AN TMD Collinear/Twist-3 pT Duke Spin Workshop Ming Liu 26

  27. Transverse SSA’s at √s = 62.4 GeV at RHIC PRL101, 042001 (2008) p0 Duke Spin Workshop Ming Liu

  28. 17 STAR pT-dependence of π0 AN • Large solid angle of FMS allows simultaneous mapping of xF vs pT with greater statistics Run3+5+6 Run8  Black: Phys.Rev.Lett.101:222001,2008 F.o.M. was smaller in run8 than in run6  More statistics needed Blue: From Spin2008 talk by J.Drachenberg, arXiv:0901.2763 Duke Spin Workshop Ming Liu

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