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

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 fafa fbfb σ FF q initial state hard scattering final state Sources of Asymmetries  Sivers  Transversity  Collins

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 x F  large rapidities  QCD test  separate Sivers and Collins  Flavor separated PDFs gamma-jet, pion-jet IFF for identified hadrons jet A N, direct photons

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

Transverse Spin Physics with PHENIX 8 PHENIX Muon Arms1.2 < | η | < 2.4  J/ Ψ  unidentified charged hadrons  heavy flavor Central Arms| η | < 0.35  identified charged hadrons  π 0, η  direct photon  J/ Ψ  heavy flavor MPC3.1 < | η | < 3.9  π 0, η

Transverse Spin Physics with PHENIX 9 Where can we look? pseudorapidity azimuth muon piston calorimeter muon arm central arms

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

Transverse Spin Physics with PHENIX 11 Forward A N Cluster contribution  decay photon  π 0  direct photon  also: hadrons in muon arms  Double transversity: A TT η 3.3 xFxF xFxF

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

Transverse Spin Physics with PHENIX 13 VTX & FVTX  Additional tracking  -2.4 < η < 2.4  Improved J/Psi mass resolution 100 MeV/c 2  Additional tracking  -2.4 < η < 2.4  Improved J/Psi mass resolution 100 MeV/c 2

Transverse Spin Physics with PHENIX 14 Where can we look? pseudorapidity azimuth muon piston calorimeter muon arm central arms

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 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, Vogelsang Phys. Rev. D 69, Bomhof, Mulder, Vogelsang and Yuan PRD 75, jet δφ

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

Transverse Spin Physics with PHENIX 18 Interference fragmentation  Di-hadron asymmetry of hadron pairs: interference fragmentation  probes δ q(x) x H 1  Fragmentation should be universal  compare with same IFF in lepton scattering  first (non-zero) results of IFF from BELLE _ _ _ _ IFF

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? pseudorapidity azimuth muon piston calorimeter muon arm central arms

Transverse Spin Physics with PHENIX 22 FoCal x Coverage x versus h (p+p, 500 GeV)  x coverage  weak p T dependence  strong  dependence  complementary to MPC

Transverse Spin Physics with PHENIX 23 photon-jet production PRL 99, (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  two dedicated trigger Resistive Plate Chamber stations per arm  approx. 1 degree pitch in azimuth Muon Trigger Upgrade  for A L of W bosons  also good for transverse asymmetries Kang, Qiu arxiv: v1

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 GeV  Muon pairs in different rapidity ranges all, central (|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  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 GeV  Electron pairs in different rapidity ranges all, central (|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 Z 0  not all is Drell Yan! all ISUB 1 (10M evts) quarksemu lepton pairs (+/-) electrons muons lepton pair in event look at lepton pairs only ɣ * decays into

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 pp ↑ PRD 70,074025

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

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

Transverse Spin Physics with PHENIX 35 BELLE IFF 8x8 m 1 m 2 binning Preliminary A. Vossen Dubna, Sept. 09 Measurement probes ( H 1 < ) 2  Non-zero and large spin- dependant FF Preliminary