Two Particle Production in Color Glass Condensate

Two Particle ProductionTwo Particle Productionin Color Glass Condensatein Color Glass Condensate

Jamal Jalilian-MarianJamal Jalilian-Marian

Institute for Nuclear TheoryInstitute for Nuclear Theory

University of WashingtonUniversity of Washington

J.J-M. + Yu.K., hep-ph/0405266J.J-M. + Yu.K., hep-ph/0405266

Color Glass Condensate Color Glass Condensate and and

High Energy ProcessesHigh Energy Processes

Some Kinematics:DISSome Kinematics:DIS

F2, FL contain all the information about the hadron (quark and gluon distribution functions)F2 ~ [q (x,Q2) + q (x,Q2)]

Perturbative QCD in pp CollisionsPerturbative QCD in pp Collisions

Weak coupling (Weak coupling (ss << 1) << 1) Collinear factorizationCollinear factorization IncoherenceIncoherence Quark, gluon distribution functions: fQuark, gluon distribution functions: faa (x, Q (x, Q22)) Distributions are universal ---> Distributions are universal ---> predictabilitypredictability

+ 1/Q2

pQCDpQCD Expansion in the couplingExpansion in the coupling

Very often one picks up Very often one picks up large logarithms (phase large logarithms (phase space), need to resum space), need to resum

DGLAP:DGLAP: BFKL: BFKL: Growth of gluon Growth of gluon

distribution functiondistribution function Violation of unitarityViolation of unitarity Saturation Saturation

Gluon SaturationGluon Saturation

High gluon density effects regulate the low kt divergence present in pQCD

Most gluons have momentum ~ Qs

Qs grows with energy (1/x), A [ ]

GLR-MQ

Color Glass CondensateColor Glass Condensate

DPG: high pDPG: high ptt, leading twist, DLA DGLAP, leading twist, DLA DGLAP CQF, anomalous dimension, leading twist, BFKLCQF, anomalous dimension, leading twist, BFKL CGC: saturation region, all twist, JIMWLKCGC: saturation region, all twist, JIMWLK

Probing the CGCProbing the CGC Deep Inelastic Scattering: ep(A) ---> eXDeep Inelastic Scattering: ep(A) ---> eX

StructureStructure functionsfunctions: F: F22, F, FLL Particle productionParticle production

Nucleus - Nucleus CollisionsNucleus - Nucleus Collisions Initial conditions (number and energy density)Initial conditions (number and energy density) MultiplicitiesMultiplicities CGC + Hydro (see T. Hirano’s talk)CGC + Hydro (see T. Hirano’s talk)

Proton (Deuteron) - Nucleus CollisionsProton (Deuteron) - Nucleus Collisions MultiplicitiesMultiplicities Single Particle productionSingle Particle production

HadronsHadrons DileptonsDileptons PhotonsPhotons

Two particle productionTwo particle production Hadron-photon correlationsHadron-photon correlations Hadron-hadron correlationsHadron-hadron correlations

Structure Functions: ProtonStructure Functions: Proton

FF22 at HERA at HERA CGC works for x < 0.01 (fig. from IIM PLB590,199, 2004)CGC works for x < 0.01 (fig. from IIM PLB590,199, 2004)

FFLL: eRHIC: eRHIC

Structure Functions: NucleiStructure Functions: Nuclei

FF22 from NMC, E665,… from NMC, E665,… Low QLow Q22 ( < 1-2 GeV ( < 1-2 GeV22 ) at small x ( < 0.01) ) at small x ( < 0.01) Light vs. heavy nucleiLight vs. heavy nuclei

CGC: scaling [no separate dependence on x, QCGC: scaling [no separate dependence on x, Q22, but on , but on QQ22/Q/Q22

ss(x)](x)] A dependence ? (figs. from Freund et al. and Armesto et al.) A dependence ? (figs. from Freund et al. and Armesto et al.)

Nucleus-Nucleus CollisionsNucleus-Nucleus Collisions

Limiting FragmentationLimiting Fragmentation

D.K.+E.L. PLB523 (2001) 79 J.J-M. Nucl-th/0211084

Particle production in dA: hadronsParticle production in dA: hadrons Forward rapidity: Forward rapidity: phase space in xphase space in xbjbj opens up opens up

Small xSmall xbjbj in nuclei (gluons) in nuclei (gluons) Large xLarge xbjbj in deuteron (quarks and gluons) in deuteron (quarks and gluons)

J. J-M.,Nucl.-th/0402080 KKT, hep-ph/0405045

Particle production in dA: dileptonsParticle production in dA: dileptons Cleaner probeCleaner probe No hadronizationNo hadronization Low ratesLow rates

J.J-M. NPA739, (2004)319

Two particle productionTwo particle production

Quark + photonQuark + photon F.G. + J.J-M., PRD66 (2002) 014021F.G. + J.J-M., PRD66 (2002) 014021

Quark + gluon , gluon + gluonQuark + gluon , gluon + gluon J.J-M. + Yu.K., hep-ph/0405266J.J-M. + Yu.K., hep-ph/0405266

Two particle correlations (KLM hep-ph/0403271)Two particle correlations (KLM hep-ph/0403271)