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,

Transverse Spin Physics with PHENIX 1

TransverseSpin Physics with the

current PHENIX

K. Oleg EyserUC Riverside

RHIC Spin: The next decadeMay 14-16, 2010 – Iowa State University, Ames


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.


Nucleon Collisions

fa

fb

σ

FFq

initialstate

hardscattering

finalstate

Sources of Asymmetries

SiversTransversityCollins


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


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


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


From now to soon…

A. Sivers & Collins meson & hadron forward AN

B. transversity driven asymmetries interference fragmentation

analysis

C. Sivers-type asymmetries heavy flavor back-to-back hadrons AN at mid-rapidity

A. Sivers & Collins meson & hadron forward AN

B. transversity driven asymmetries interference fragmentation

analysis

C. Sivers-type asymmetries heavy flavor back-to-back hadrons AN at mid-rapidity


PHENIX

Muon Arms 1.2 < | η | < 2.4 J/Ψ unidentified charged hadrons heavy flavor

Central Arms | η | < 0.35 identified charged hadrons π0, η direct photon J/Ψ heavy flavor

MPC 3.1 < | η | < 3.9 π0, η


Where can we look?

pseudorapidity-4 -3 -2 -1 0 1 2 3 4

azi

muth

muon p

isto

n c

alo

rim

ete

r

muon p

isto

n c

alo

rim

ete

r

muon a

rm

muon a

rm

centralarms


Forward AN

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


Forward AN

Cluster contribution decay photon π0

direct photon

also: hadronsin muon arms

Double transversity: ATT

η < 3.3 η > 3.3

xF xF


Heavy flavor

a.u

. (p

yth

ia)

di-muonxF ≈ -1

di-electronxF = 0

di-muonxF ≈ 1

200 GeV500 GeV

J/Psi single spin asymmetry production mechanism gluon dynamics larger xFlever arm?

Run6 / Run8 statistics

xF


VTX & FVTX

Additional tracking -2.4 < η < 2.4 Improved J/Psi mass

resolution 100 MeV/c2

Additional tracking -2.4 < η < 2.4 Improved J/Psi mass

resolution 100 MeV/c2


Where can we look?


azi

muth

muon p

isto

n c

alo

rim

ete

r

muon p

isto

n c

alo

rim

ete

r

muon a

rm

muon a

rm

centralarms


Heavy Flavorsingle leptons / no full D-meson reconstruction dominated by charm production in kinematic range no transversity (no transversity x Collins)


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

)( TT kpS

jet

jetδφ


Di-hadron Correlations In the central arm triggered

neutral pion

associated hadron

other possible combinations


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

21 ,

,

hh

UTA

++

++__

__qq

IFFIFF


IFF at mid-rapidity


A forward calorimeter

Si-W calorimeter Combines tracking with calorimetry Excellent gamma-pion separation


Where can we look?


azi

muth

muon p

isto

n c

alo

rim

ete

r

muon p

isto

n c

alo

rim

ete

r

muon a

rm

muon a

rm

centralarms


FoCal x Coverage

x versus h (p+p, 500 GeV)

x coverage weak pT dependence

strong dependence complementary to

MPC


photon-jet productionPRL 99, 212002 (2007)standard partonic cross sectionsmax gluon Siversmax Boer-Muldersgluonic-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…


two dedicated trigger Resistive Plate Chamber stations per arm

approx. 1 degree pitch in azimuth

Muon Trigger Upgrade

for AL of W bosons also good for

transverse asymmetriesKang, Qiu arxiv:0903.3629v1


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?


Simulation @ 500 GeV Muon pairs in different rapidity rangesall, central (|y|<1), forward (|y|>2), very forward (|y|>3)

minimum bias*

jet processesdiffractive, multiplewide rapidity (±4)very basic cuts

Drell Yanqualitative

not properly scaled≈ x10-6


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


Simulation @ 500 GeV Electron pairs in different rapidity rangesall, central (|y|<1), forward (|y|>2), very forward (|y|>3)

minimum bias*

jet processes

diffractive, multiple

wide rapidity (±4)

very basic cuts

Drell Yanqualitative

not properly scaled≈ x10-6


Electron/muon pairs PYTHIA ISUB 1 is virtual photon and Z0

not all is Drell Yan!all ISUB 1 (10M evts)

quarks e mu quarks e mu

lepton pairs (+/-)

electronsmuons

lepton pair in event

look at leptonpairs only

ɣ*decays

into


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


backup


Heavy Flavor

pp↑→DX @LO

PRD 70,074025


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


IFF Definitions

1 2

1 2

1 2

, : momenta of protons

, : momenta of hadrons

( ) / 2

: proton spin orientation

A B

h h

C h h

C h h

B

P P

P P

P P P

R P P

S

^^^^^^^^^^^^^^^^^^^^^^^^^^^^

^^^^^^^^^^^^^^^^^^^^^^^^^^^^

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

^^^^^^^^^^^^^^

1hP^^^^^^^^^^^^^^

2hP^^^^^^^^^^^^^^

AP^^^^^^^^^^^^^^

BP^^^^^^^^^^^^^^

CP^^^^^^^^^^^^^^

BS^^^^^^^^^^^^^^

pp hhX

1 2hadron plane: ,

scattering plane: ,

h h

C B

P P

P P

^^^^^^^^^^^^^^^^^^^^^^^^^^^^

^^^^^^^^^^^^^^^^^^^^^^^^^^^^ : from scattering plane

to hadron planeR : from polarization vector

to scattering plane S

Bacchetta and Radici, PRD70, 094032 (2004)

2 CR^^^^^^^^^^^^^^


BELLE IFF

8x8 m1 m2 binning

Preliminary

A. Vossen Dubna, Sept. 09

Measurement probes ( H1< )2

Non-zero and large spin-dependant FF

Preliminary

Documents

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,