Transverse Spin Physics at RHIC II M. Grosse Perdekamp

University of Illinois and RIKEN BNL Research Center

QCD N06 , June 12 - 16, 2006, Rome, Italy

o Strong Interaction Physics at BNL

RHIC RHIC II e-RHIC

o RHIC II

Luminosity and Detector Upgrades Overview of the Physics Program

o Transverse Spin Physics

Collins and Interference Fragmentation Drell Yan

STARSTAR

pp2pppp2pp

Transverse Spin Physics at RHIC II 2 June 16th

Strong Interaction Physics at

o Quark Matter at high Temperatures and Densities

ion-ion collisions (Cu-Cu, Au-Au: √sNN=22.5, 62, 130, 200 GeV)

o Proton Spin Structure

polarized proton-proton collisions (p-p: √s=200 to 500 GeV)

o Low-x and high parton densities

ion-deuteron collisions (d-Au: √sNN=200 GeV)

very active field: 74 PRL letters in the first 5 years

high luminosity, detector upgrades

high luminosity, dedicated transverse spin experiment?

high luminosity, detector upgrades

polarized e-p

polarized e-p

RHIC IIe-RHICRHIC

RHIC II

Transverse Spin Physics at RHIC II 3 June 16th

Transverse spin program at RHIC is luminosity limited

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 by 2009 at 200 GeV

∫Ldt ~275pb-1 delivered

∫Ldt ~100pb-1 accepted(eg. PHENIX: vertex cut,trigger efficiencies, dutyfactor)

∫Ldt ~25 pb-1 transverse

RH

IC II

Physics channel Luminosity?

Dedicated Drell Yan experiment for transverse spin physics at RHIC ?

Transverse Spin Physics at RHIC II 4 June 16th

(I) Electron Cooling in RHIC to increase luminosity for HI by factor 10

(II) Detector Upgrades in PHENIX and STAR

(III) Drell Yan Experiment for Transverse Spin?

RHIC II – Definition

RHIC II upgrades will be carefully coordinated with the effort to build a electron ion collider RHIC as “QCD Lab”

target date 2012

Transverse Spin Physics at RHIC II 5 June 16th

RHIC II: Luminosity Upgrade with Electron Cooling (from Thomas Roser)

Transverse Spin Physics at RHIC II 6 June 16th

• 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!

p-p Expectations for the RHIC II Luminosity Upgrade

Transverse Spin Physics at RHIC II 7 June 16th

RHIC five complementary experiments

RHIC II: Room for New Ideas!

pp2pppp2pp100% transverse !

Transverse Spin Physics at RHIC II 8 June 16th

RHIC II: Upgrades in STAR and PHENIX

FMS (Forward Meson Spectrometer)

TOF HFT (Heavy Flavor Tracker)

Tracking UpgradeDAQ

HBD (Hadron Blind Detector)

Silicon (VTX, FVTX)Muon TriggerForward Calorimeter

T-SPHINX

RHIC II: Transverse Spin Physics High Rate (N) Experiment

Transverse Spin Physics at RHIC II 9 June 16th

T-SPHINX

RHIC II: Transverse Spin Physics High Rate (N) Experiment

Large acceptance Drell Yan experiment:

(1) 100 % Transverse Spin x 4 (2) Large acceptance -3<η<+3 x 8 (3) Electron cooling x 2.5 (4) Mini-quads x 4 ~300Physics: Sivers-, Transversity-, Boer-Mulder-distributions in Drell Yan lepton pair production at RHIC.

Relative gain in ∫LdtCompared to PHENIX

Transverse Spin Physics at RHIC II 10

June 16th

Luminosity upgrade

High statistics Au-Au, 500 GeV pp RHIC II

RHIC II Schedule: Detector Upgrades + Luminosity

Transverse Spin Physics at RHIC II 11

June 16th

RHIC II Science Workshops: Spin Physics

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)

BNL, October 7-8, 2005

Science at RHIC II report: Summer 2006

Transverse Spin Physics at RHIC II 12

June 16th

Physics Channels for RHIC II

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

(RHIC II Spin Working Group, E. Sichterman, M. Stratmann, MGP, et al.)

Transverse Spin Physics at RHIC II 13

June 16th

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.

Transverse Spin Physics at RHIC II 14

June 16th

Transversity from Interference Fragmentation(Efremov, Collins, Heppelman, Ladinsky,

Atru, Jaffe, Jin, Tan, Radici, Jacob, Bacchetta)

NN

NN

PA

beamT

1

Func.tion Fragmenta Pol.: )(ˆ

quark DFsty Transversi : )(

d Pair Yiel Pion:

zq

xq

N

QCD analysis of Belle IFF and RHICAT in IFF to extract transversity

Transverse Spin Physics at RHIC II 15

June 16th

Projected statistical errors in one invariantmass bin 800 MeV < m < 950 MeV

Integrated Luminosity for RHIC II ~ 125 pb-1

pair vsAsymmetry on iesUncertaint Tp

1%

2%

IFF from BelleAT from STAR+PHENIX

Transverse Spin Physics at RHIC II 16

June 16th

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

Drell Yan Physics with T-SPHINX

)()( 21 xqxqATT

M

SkPkxfxqA PTq

TT

)ˆ(

),()( 2211

M

SkPkxh

M

SkPkxhN qqqq

)ˆ(),(

)ˆ(),()( 2

212

11

Transverse Spin Physics at RHIC II 17

June 16th

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!

Transverse Spin Physics at RHIC II 18

June 16th

Sivers-Asymmetries, AT in Drell Yan (J. Collins et al.)

STAR for 125pb-1

T-SPHINX1250 pb-1

o 10 o’clock 100% transverse polarization

o mini-quads

o acceptance: -3 < η < 3

x 300 in ∫Ldt

AT

Q=4GeV Q=20GeVQ=4GeV Q=20GeVAT

Precision measurement of Sivers distributions!

Transverse Spin Physics at RHIC II 19

June 16th

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 Yan1.25fb-1, large acceptance detector for Drell Yan

This measurement appears to bealso possible at 500 GeV

Transverse Spin Physics at RHIC II 20

June 16th

RHIC II Summary

o 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.