Future Opportunities in Transverse Spin Physic at RHIC

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Future Opportunities inTransverse Spin Physic at
RHIC

• Strong Interaction Physics at BNL
• RHIC ? e-RHIC
• RHIC from present to future
• Detector Upgrades
• Overview of the Physics Program
• Transverse Spin Physics
• Collins and
• Interference Fragmentation
• Sivers
• Drell Yan

pp2pp
Matthias Grosse-Perdekamp, Univ. Illinois Les
Bland, Brookhaven National Laboratory
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Strong Interaction Physics at
RHIC, now
RHIC, future
e-RHIC

• Quark Matter at high
• Temperatures and Densities
• ion-ion collisions (Cu-Cu, Au-Au vsNN22.5,
  62, 130, 200 GeV)
• Proton Spin Structure
• polarized proton-proton collisions (p-p
  vs62.4, 200, 500 GeV)
• Low-x and high parton densities
• ion-deuteron collisions (d-Au vsNN200 GeV)

10 x higher luminosity, detector upgrades
?RHICLdt ? 2 fb-1, high luminosity transverse
spin running?
polarized e-p
very active field gt 90 PRL letters in the
first 6 years
(high luminosity) forward detector upgrades
e-A scattering
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RHIC Run 6 Performance
60 beam polarization and 1MHz interaction rate
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Luminosity Projection (no mini-quads)
Expect polarization of 70 and luminosity of
?s 200 GeV 100 pb-1 in 10 week run
?s 500 GeV 250 pb-1 in 10 week run
http//spin.riken.bnl.gov/rsc/report/RHIC_spin_LRP
07.pdf
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Expectations for Future RHIC Operations

• Factor 2-3 increase in pp luminosity
• Improvement in ratio of recorded/delivered
  luminosity (vertex)
• Small improvements in polarization
• Polarized 3He2 or polarized d beams may be
  possible
• Maximum energy vs 650 GeV
• Mini-quads at the IRs might provide additional
  increase in luminosity.

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Some Issues

• delivered versus recorded integrated luminosity
• luminosity monitoring at high luminosity
• ?s?200 GeV versus ?s500 GeV collisions
• longitudinal versus transverse polarization
  collisions
• More, later

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RHIC Upgrades in STAR and PHENIX

• Luminosity expectations (example, PHENIX)
• ?Ldt 15 pb-1 2007
• ?Ldt 85 pb-1 2008 2012, vs200 GeV
• ?Ldt 300 pb-1 2008 2012, vs500 GeV
• ?Ldt 1300 pb-1 2013 2016, vs500 GeV
• Upgrades will be available for most of
• RHIC spin luminosity!
• Completed / In Progress / Future

HBD (Hadron Blind Detector) Silicon (VTX,
FVTX) Muon Trigger Forward Calorimeter
FMS (Forward Meson Spectrometer) Time of Flight
(TOF) HFT (Heavy Flavor Tracker) Forward
Tracking Upgrade DAQ 1000
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Transverse spin program at RHIC is luminosity
limited
Physics channel Luminosity?
AN
very good AN(back-to-back) good
AT (Collins FF)
limited AT (Interference FF) limited ATT
(Jets) not studied AT
(Drell Yan) --- ATT( Drell Yan)
---

RHIC by 2009 at 200 GeV ?Ldt 275pb-1
delivered ?Ldt 100pb-1 accepted (eg. PHENIX
vertex cut, trigger efficiencies, duty factor)
? ?Ldt 25 pb-1 transverse
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Transverse Spin Physics at RHIC with Large ?Ldt
Transversity correlation between transverse
proton spin and
quark spin Sivers correlation
between transverse proton
spin and quark
transverse momentum Boer/Mulders
correlation between transverse quark spin
and quark
transverse momentum
Collins and Interference FF ?Ldt gt 30 pb-1
AT in Drell Yan ?Ldt 250 pb-1
A(f0) Drell Yan ?, not studied
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Transversity Tensor Charge froma Global
Analysys of e-p, p-p and ee-
Factorization Universality ?!
Belle
RHIC / GSI
Transversity Tensor Charge
Theory
Lattice QCD Tensor Charge
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Transversity from Inter-
ference Fragmentation in pp
(Efremov, Collins, Heppelman, Ladinsky, Atru,
Jaffe, Jin, Tan, Radici, Jacob, Bacchetta)
QCD analysis of Belle IFF and RHIC AT in IFF to
extract transversity
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Projected Errors at for ?Ldt125 pb-1 at RHIC
Projected statistical errors in one
invariant mass bin 800 MeV lt m lt 950 MeV
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IFF from Belle AT from STARPHENIX
M. Grosse-Perdekamp, RBRC Workshop on Future
Transversity Measurements, BNL (2000)
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SSA from pions to Drell-Yan
Many issues have already been discussed at this
workshop about transverse SSA for inclusive pion
production at RHIC. A future transverse SSA
measurement of Drell-Yan at RHIC is possible,
with some optimization to the experiments. But,
there is need and opportunity for goals
intermediate between inclusive pion and Drell-Yan
SSA at RHIC ? Large-Rapidity Prompt Photon
Transverse SSA
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Sample decays on FPDRun-6 / 6.8 pb-1 / 60
polarization
With FPD module size and electronic dynamic
range, have gt95 probability of detecting second
photon from p0 decay.
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Where do decay partners go?
m p0(h) di-photon parameters zgg
E1-E2/(E1E2) fgg opening angle Mm 0.135
GeV/c2 (p0) Mm0.548 GeV/c2 (h)

• Gain sensitivity to direct photons by making
  sure we have high probability to catch decay
  partners
• This means we need dynamic range, because
  photon energies get low (0.25 GeV), and
  sufficient area (typical opening angles few
  degrees at our h ranges).

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Single ? events in inner FPD cells PYTHIA
6.222 Simulations
L0.9 pb-1 3.8?1010 calls
? from ?0 (Without VETO)
? from ? (Without VETO)
Direct-?
? from ?0 (With VETO)
E?
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Sivers in SIDIS vs Drell Yan
Transverse-Spin Drell-Yan Physics at RHIC L.
Bland, S.J. Brodsky, G. Bunce, M. Liu, M.
Grosse-Perdekamp, A. Ogawa, W. Vogelsang, F.
Yuan http//spin.riken.bnl.gov/rsc/write-up/dy_fin
al.pdf

• Important test at RHIC of the fundamental QCD
  prediction of the non-universality of the Sivers
  effect!
• requires very high luminosity ( 250pb-1)

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Non-universality of Sivers Asymmetries Unique
Prediction of Gauge Theory !
Simple QED example
Drell-Yan repulsive
DIS attractive
Same in QCD
As a result
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Experiment SIDIS vs Drell Yan SiversDIS -
SiversDY Test QCD Prediction of
Non-Universality
HERMES Sivers Results
RHIC Drell Yan Projections
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Sivers Amplitude
Markus Diefenthaler DIS Workshop Munchen, April
2007
0
0.1 0.2 0.3 x
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Benchmarking Simulations
pp ? J/?X ? ll-X, ?s200 GeV
PHENIX, hep-ex/0611020
mm- 1.2lthlt2.2
ee- hlt0.35
J/? is a critical benchmark that must be
understood before Drell-Yan
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Dilepton Backgrounds
Drell-Yan
J/?
?
?
Isolation needed to discriminate open heavy
flavor from DY
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Rapidity and Collision Energy
Large rapidity acceptance required to probe
valence quark Sivers function
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Summary of Transverse SSA Drell-Yan

• 250 pb-1 transverse polarization Drell-Yan data
  sample probes Sivers function sign relative to
  SIDIS.
• Isolation required to discriminate low-mass DY
  from open-heavy flavor.
• Large rapidity will require tracking for
  charge-sign discrimination.
• Polarized deuteron collisions, with forward
  spectator tag, could probe flavor dependence.