1. Transverse Spin Physics at RHIC II
M. Grosse Perdekamp
University of Illinois and
RIKEN BNL Research Center
Strong Interaction Physics at BNL
RHIC  RHIC II  e-RHIC
RHIC II
Luminosity and Detector Upgrades
Overview of the Physics Program
Transverse Spin Physics
Collins and
Interference Fragmentation
Drell Yan
pp2pp
STAR
QCD N06 , June , 2006, Rome, Italy

2. Strong Interaction Physics at
e-RHIC
RHIC II
RHIC
Quark Matter at high
Temperatures and Densities
ion-ion collisions (Cu-Cu, Au-Au: √sNN=22.5, 62, 130, 200 GeV)
Proton Spin Structure
polarized proton-proton collisions (p-p: √s=200 to 500 GeV)
Low-x and high parton densities
ion-deuteron collisions (d-Au: √sNN=200 GeV)
high luminosity, detector upgrades
high luminosity, dedicated transverse spin experiment?
polarized e-p
very active field:
 74 PRL letters
in the first 5 years
RHIC II
high luminosity, detector upgrades
polarized e-p
June 16th
Transverse Spin Physics at RHIC II

3. Transverse spin program at RHIC is luminosity limited
Physics channel Luminosity?
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
AN yes, very good
AN(back-to-back) good
AT (Collins FF) fair
AT (Interference FF) limited
ATT (Jets) not studied experimentally
AT (Drell Yan)
ATT( Drell Yan)
Direct photons, Ws
(AN,AT(CFF, IFF))
RHIC II
Dedicated Drell Yan
experiment for transverse
spin physics at RHIC ?
June 16th
Transverse Spin Physics at RHIC II

4. Transverse Spin Physics at RHIC II
RHIC II – Definition
Electron Cooling in RHIC to increase luminosity for HI by factor 10
Detector Upgrades in PHENIX and STAR
Drell Yan Experiment for Transverse Spin?
target date
2012
RHIC II upgrades will be carefully coordinated
with the effort to build a electron ion collider
 RHIC as “QCD Lab”
June 16th
Transverse Spin Physics at RHIC II

5. Transverse Spin Physics at RHIC II
RHIC II: Luminosity Upgrade with Electron Cooling
(from Thomas Roser)
June 16th
Transverse Spin Physics at RHIC II

6. p-p Expectations for the RHIC II Luminosity Upgrade
Factor 2-3 increase in pp luminosity
Small improvements in polarization
Maximum energy √s = 650 GeV
Operation at 20-30% higher energy possible
Can have polarized 3He2+ beams
Mini-quads at one IP can boost luminosity by a factor 3-5
 assume factor 10 possible with mini-quads, if mini-
quads can be integrated with detector design!
June 16th
Transverse Spin Physics at RHIC II

7. RHIC  five complementary experiments
RHIC II: Room for New Ideas!
RHIC  five complementary experiments
100% transverse !
pp2pp
June 16th
Transverse Spin Physics at RHIC II

8. RHIC II: Transverse Spin Physics High Rate (N) Experiment
RHIC II: Upgrades in STAR and PHENIX
T-SPHINX
HBD (Hadron Blind Detector)
Silicon (VTX, FVTX)
Muon Trigger
Forward Calorimeter
FMS (Forward Meson Spectrometer)
TOF
HFT (Heavy Flavor Tracker)
Tracking Upgrade
DAQ
June 16th
Transverse Spin Physics at RHIC II

9. RHIC II: Transverse Spin Physics High Rate (N) Experiment
T-SPHINX
Large acceptance Drell Yan experiment:
(1) 100 % Transverse Spin x 4
(2) Large acceptance -3<η< x 8
(3) Electron cooling x 2.5
(4) Mini-quads x 4
~300
Physics: Sivers-, Transversity-,
Boer-Mulder-distributions
in Drell Yan lepton pair
production at RHIC.
Relative gain in ∫Ldt
Compared to PHENIX
June 16th
Transverse Spin Physics at RHIC II

10. Transverse Spin Physics at RHIC II
RHIC II Schedule: Detector Upgrades + Luminosity
High statistics Au-Au, 500 GeV pp RHIC II
Luminosity upgrade
June 16th
Transverse Spin Physics at RHIC II

11. Science at RHIC II report: Summer 2006
RHIC II Science Workshops: Spin Physics
BNL, October 7-8, 2005
Transverse spin physics: S. Menzel (Bochum), L. Gamberg (Penn State), J. Soffer (Marseille),
M. Burkardt (New Mexico), F. Yuan (RBRC), M. Radici (Pavia)
Hyperons : Z. Liang (Shandong), Q. Xu (Shandong+LBL), K. Sudoh (KEK)
W-physics: P. Nadolsky (Argonne), K. Sudoh (KEK), J. Soffer (Marseille)
Beyond the SM: J. Soffer (Marseille), D. Maitre (Zurich)
Science at RHIC II report: Summer 2006
June 16th
Transverse Spin Physics at RHIC II

12. Physics Channels for RHIC II
(RHIC II Spin Working Group,
E. Sichterman, M. Stratmann, MGP, et al.)
Precision measurement of the proton helicity structure
o ∆G(x) and ∆q(x), ∆q(x) with high luminosity in multiple channels with
available detector upgrades. Extend measurements to 3He  neutron.
(can this be done with high polarization + intensity??)
 minimize errors and increase x-coverage of ∆G(x) for precision
measurement of the first moment of the spin-dependent gluon
distribution ∆G=ʃ ∆G(x)dx.
 observe scale evolution of the first moment.
 global QCD analysis for best knowledge of polarized nucleon structure + pdfs
Precision cross section measurements + QCD analysis
o Measure cross sections in direct photon production, inclusive jet + hadron production
as input to QCD analysis to improve knowledge of
 G(x) at large x
 Gluon fragmentation function
June 16th
Transverse Spin Physics at RHIC II

13. Transverse Spin Physics at RHIC II
Physics Channels for RHIC II
Polarization of the strange sea
o Access ∆s(x) through inclusive anti-Lambda production
and charm associated W-production (very luminosity
hungry!)
 study polarization of the strange sea
 verify ∆s from DIS
Transverse Spin Physics
o Extract transversity quark distributions from precision
measurements of asymmetries in Collins- and interference
fragmentation.
o Measure transversity-, Sivers- and Boer-Mulders
asymmetries in Drell Yan. AN in direct photon and
W production.
June 16th
Transverse Spin Physics at RHIC II

14. QCD analysis of Belle IFF and RHIC AT in IFF to extract transversity
Transversity from Interference Fragmentation
(Efremov, Collins, Heppelman, Ladinsky,
Atru, Jaffe, Jin, Tan, Radici, Jacob, Bacchetta)
QCD analysis of Belle IFF and RHIC
AT in IFF to extract transversity
June 16th
Transverse Spin Physics at RHIC II

15. Integrated Luminosity for RHIC II ~ 125 pb-1
Projected statistical errors in one invariant
mass bin 800 MeV < m < 950 MeV 1% 2%
IFF from Belle
AT from STAR+PHENIX
June 16th
Transverse Spin Physics at RHIC II

16. Drell Yan Physics with T-SPHINX
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
June 16th
Transverse Spin Physics at RHIC II

17. Transverse Spin Physics at RHIC II
Sivers-Asymmetries, AT in Drell Yan (J. Collins et al.)
Sensitivity to anti-quark Sivers distribution (not probed at GSI)
Sensitivity to sign with respect to DIS!
June 16th
Transverse Spin Physics at RHIC II

18. Precision measurement of Sivers distributions!
Sivers-Asymmetries, AT in Drell Yan (J. Collins et al.)
Q=4GeV
Q=4GeV
Q=20GeV
Q=20GeV AT AT
STAR for 125pb-1
T-SPHINX
1250 pb-1
o 10 o’clock  100%
transverse polarization
o mini-quads
o acceptance: -3 < η < 3
 x 300 in ∫Ldt
Precision measurement of Sivers distributions!
June 16th
Transverse Spin Physics at RHIC II

19. Projections for pp at 200 GeV and 1250 pb-1
ATT for Drell Yan with dedicated DY detector
projections for 1250pb-1 of running,
5-10% higher polarization, with RHIC II
luminosities and large acceptance
Drell Yan
1.25fb-1, large acceptance
detector for Drell Yan
This measurement appears to be
also possible at 500 GeV
June 16th
Transverse Spin Physics at RHIC II

20. Transverse Spin Physics at RHIC II
RHIC II Summary
Precision measurements of asymmetries in
Collins- and Interference-Fragmentation to map
out quark transversity distributions.
o Drell Yan
AT (a) STAR can test expected sign change for
the Sivers function at low invariant mass.
(b) Dedicated DY experiment possible to extract
Sivers quark distribution. Sensitive to anti-
quark distributions!
ATT Clean measurement of anti-quark and possibly quark transversity distributions
o Access to Ws and direct photons.
June 16th
Transverse Spin Physics at RHIC II