Transverse Spin Physics with the current PHENIX

1. RHIC Spin: The next decade May 14-16, 2010 – Iowa State University, Ames TransverseSpin Physics with the current PHENIX K. Oleg Eyser UC Riverside Transverse Spin Physics with PHENIX

2. Disclaimer • How do we get from now to the future? • The physics should be our main objective. • We should not measure something just because we can measure it. • This will be part summary and part outlook of how the current PHENIX can do to contribute to an exciting physics program. • A less bound perspective will follow in the next talk. Transverse Spin Physics with PHENIX

3. Nucleon Collisions initial state hard scattering Sources of Asymmetries • Sivers • Transversity • Collins final state fa FFq σ fb Transverse Spin Physics with PHENIX

4. Three major questions RHIC Spin Plan 2007/2008 • How do gluons contribute to the proton spin? • large x range • What is the flavor structure of the polarized sea in the nucleon? • What are the origins of transverse-spin phenomena in QCD? • Transversity • Connections to orbital angular momentum Transverse Spin Physics with PHENIX

5. Input for theory… • Separate Sivers and Collins • Hadron in jet • Di-hadron correlation • Transversity • two-hadron interference fragmentation • Non-universality test of Sivers • Drell Yan • gamma-jet Transverse Spin Physics with PHENIX

6. Objectives • Transverse spin phenomena • asymmetries at high xF • large rapidities • QCD test • separate Sivers and Collins • Flavor separated PDFsgamma-jet, pion-jetIFF for identified hadronsjet AN, direct photons Transverse Spin Physics with PHENIX

7. From now to soon… • Sivers & Collins • meson & hadron forward AN • transversity driven asymmetries • interference fragmentation analysis • Sivers-type asymmetries • heavy flavor • back-to-back hadrons • AN at mid-rapidity Transverse Spin Physics with PHENIX

8. PHENIX • Central Arms | η | < 0.35 • identified charged hadrons • π0,η • direct photon • J/Ψ • heavy flavor • Muon Arms 1.2 < | η | < 2.4 • J/Ψ • unidentified charged hadrons • heavy flavor • MPC 3.1 < | η | < 3.9 • π0, η Transverse Spin Physics with PHENIX

9. Where can we look? central arms azimuth muon arm muon arm muon piston calorimeter muon piston calorimeter -4 -3 -2 -1 0 1 2 3 4 pseudorapidity Transverse Spin Physics with PHENIX

10. Forward AN • Transversity x Collins • Sivers Processs contribution to pi0, eta=3.3, sqrt(s)=200 GeV Guzey et al, PLB 603,173 (2004) • very valuable for a global analysis Transverse Spin Physics with PHENIX

11. η < 3.3 η > 3.3 xF xF Forward AN • also: hadronsin muon arms • Double transversity: ATT • Cluster contribution • decay photon • π0 • direct photon Transverse Spin Physics with PHENIX

12. 500 GeV Run6 / Run8 statistics xF Heavy flavor • J/Psi single spin asymmetry • production mechanism • gluon dynamics • larger xFlever arm? di-muon xF ≈ -1 di-electron xF = 0 di-muon xF ≈ 1 200 GeV a.u. (pythia) Transverse Spin Physics with PHENIX

13. VTX & FVTX • Additional tracking • -2.4 < η< 2.4 • Improved J/Psi mass resolution 100 MeV/c2 Transverse Spin Physics with PHENIX

14. Where can we look? central arms azimuth muon arm muon arm muon piston calorimeter muon piston calorimeter -4 -3 -2 -1 0 1 2 3 4 pseudorapidity Transverse Spin Physics with PHENIX

15. Heavy Flavor • single leptons / no full D-meson reconstruction • dominated by charm production in kinematic range • no transversity (no transversity x Collins) Transverse Spin Physics with PHENIX

16. jet jet δφ Back-to-back jets The Sivers effect can manifest itself as an azimuthal asymmetry in back-to-back jets in polarized p+p collisions. Boer, VogelsangPhys. Rev. D 69, 094025 Bomhof, Mulder, Vogelsang and YuanPRD 75, 074019 Transverse Spin Physics with PHENIX

17. other possible combinations Di-hadron Correlations • In the central arm • triggered • neutral pion • associated • hadron Transverse Spin Physics with PHENIX

18. IFF _ + _ + Interference fragmentation • Di-hadron asymmetry of hadron pairs:interference fragmentation • probes δq(x) x H1 • Fragmentation should be universal • compare with same IFF in lepton scattering • first (non-zero) results of IFF from BELLE Transverse Spin Physics with PHENIX

19. IFF at mid-rapidity Transverse Spin Physics with PHENIX

20. A forward calorimeter • Si-W calorimeter • Combines tracking with calorimetry • Excellent gamma-pion separation Transverse Spin Physics with PHENIX

21. Where can we look? central arms azimuth muon arm muon arm muon piston calorimeter muon piston calorimeter -4 -3 -2 -1 0 1 2 3 4 pseudorapidity Transverse Spin Physics with PHENIX

22. FoCal x Coverage • x coverage • weak pT dependence • strong h dependence • complementary to MPC x versus h (p+p, 500 GeV) Transverse Spin Physics with PHENIX

23. photon-jet production PRL 99, 212002 (2007) standard partonic cross sections max gluon Sivers max Boer-Mulders gluonic-pole cross sections 200 GeV • Moment is dominated by quark Sivers function • Validation of framework • Sign change is a fundamental QCD prediction • Would require substantial transverse running… Transverse Spin Physics with PHENIX

24. Muon Trigger Upgrade • for AL of W bosons • also good for transverse asymmetriesKang, Qiu arxiv:0903.3629v1 • two dedicated trigger Resistive Plate Chamber stations per arm • approx. 1 degree pitch in azimuth Transverse Spin Physics with PHENIX

25. Excursion: Drell Yan, again… • Too good to be ignored • No fragmentation • Separate initial from final state effects • Sivers vs. Collins • If we could choose… • What is the best kinematic range? • What signal/background can we achieve? • What energy yields the optimum result? • Which flavor is most promising? Transverse Spin Physics with PHENIX

26. Simulation @ 500 GeV • Muon pairs in different rapidity ranges all, central (|y|<1),forward (|y|>2),very forward (|y|>3) minimum bias* jet processes diffractive, multiple wide rapidity (±4) very basic cuts Drell Yan qualitative not properly scaled ≈ x10-6 Transverse Spin Physics with PHENIX

27. Very forward muons • Modest upgrade • Muon detectors • Choice of technology • RPC or other • Background • Behind muon piston • Impact on ZDC • Magnetic field • Charge separation • Only in south arm Transverse Spin Physics with PHENIX

28. Simulation @ 500 GeV • Electron pairs in different rapidity ranges all, central (|y|<1),forward (|y|>2),very forward (|y|>3) minimum bias* jet processes diffractive, multiple wide rapidity (±4) very basic cuts Drell Yan qualitative not properly scaled ≈ x10-6 Transverse Spin Physics with PHENIX

29. Electron/muon pairs • PYTHIA ISUB 1 is virtual photon and Z0 • not all is Drell Yan! all ISUB 1 (10M evts) lepton pairs (+/-) electrons muons lepton pair in event look at leptonpairs only ɣ* decaysinto quarks e mu quarks e mu Transverse Spin Physics with PHENIX

30. Summary • Different origins of spin asymmetries • Focus on what we (as in hadron collisions) can do best • Finish current spin plan • We need a thorough investigation for future upgrades Transverse Spin Physics with PHENIX

31. backup Transverse Spin Physics with PHENIX

32. Heavy Flavor PRD 70,074025 pp↑→DX @LO Transverse Spin Physics with PHENIX

33. Forward AN Charged Hadrons • Unidentified charged hadron AN • Asymmetries corrected for bin sharing and interactions in magnet/absorber • Non-zero AN persists to moderate pseudorapidity Transverse Spin Physics with PHENIX

34. IFF Definitions Bacchetta and Radici, PRD70, 094032 (2004) Transverse Spin Physics with PHENIX

35. BELLE IFF Preliminary Preliminary • Measurement probes ( H1< )2 • Non-zero and large spin-dependant FF Transverse Spin Physics with PHENIX 8x8 m1 m2 binning A. Vossen Dubna, Sept. 09