RHIC/HENP Physics Program: Connections with LANL Theory

Mike Leitch – P-25, leitch@lanl.govParton structure, modification in nuclei, spin-dependence and the

Quark Gluon Plasma(QGP):

• Flavor asymmetry of the nucleon sea and its spin-dependence; origins from meson-cloud of the nucleon

• Gluon structure functions, their shadowing in nuclei and spin-dependence

• Energy loss & fragmentation of partons (light & heavy) in nuclei to elucidate the parton dynamics of these processes. Contrast with same in hot/high-density matter.

• Heavy-quark (open and closed-c,b) production and suppression in cold nuclei & in QGP.

• Characteristics of heavy-ion collisions through charged particle multiplicities, reaction plane measurements, etc.

FNAL E866/NuSea

ACU, ANL, FNAL, GSU, IIT, LANL, LSU, NMSU, UNM, ORNL, TAMU, Valpo

A measurement of )(/)( xuxdAnti-quark asymmetry in the Nucleon Sea

E866/NuSea: 800 GeV p-A (Fermilab)PRL 84, 3256 (2000)

• J/Ψ and Ψ’ similar at large xF where they both correspond to a traversing the nucleus•but Ψ’ absorbed more strongly than J/Ψ near mid-rapidity (xF ~ 0) where the resonances are beginning to be hadronized in nucleus.

open charm: no A-depat mid-rapidity

HadronizedJ/

cc

PT Broadening at 800 GeV

(pT) shape is independent of xF & same for NA3 at a lower energy

cc

MagnetMagnetMuon IdentifiersMuon Identifiers

MuonMuon12.5°12.5°

35°35° 35°35°

10.5°10.5°

2 Muon Trackers = 2 Muon Trackers =

2x3 stations2x3 stations

2 Muon Identifiers 2 Muon Identifiers

= 2x5 planes= 2x5 planes

South Arm: South Arm: Began operationsin 2001-2002 run.

North Arm:North Arm:Installed in 2002, now running.

PHENIX Muon ArmsPHENIX Muon Arms

Acceptance : 1.2 < || < 2.4

Muon minimum momentum ~ 2 GeV/c

TrackingTrackingStationsStations

South Muon Arm North Muon Arm

Multiplicity & Vertex Detector

p+p J/ +-

yLA

N

dy

dB J

BBCrecocc

J

y

Jr

/

/

7.1

/

Br (J/+-) dJ//dy|y=1.7. = 37 7 (stat.) 11 (syst.) nb PHENIX Preliminary

• NJ/ = 36 7 (stat.) 4 (syst.)• Accreco = 0.0163 0.031 BBC

J/ L = 0.60 0.12 nb-1

y: rapidity coverage = 1.0

p+ps=200GeV

Raufeisen & Peng hep-ph/0211422

Relating parton model and color dipole formulation of heavy quark hadroproduction

PHENIX J/ data from Run-II

theoreticaluncertainty

Cooper, Liu, Mottola, Nayak, “Color Octet Contribution to High pT J/ Production in pp Collisions at RHIC”

Direct and feed-down J/ production in color-octec and –singlet channels at 200 & 500 GeV

Analysis of our p-A Drell-Yan data (E772) using the color-dipole model. Dashed lines with shadowing only; solid lines with parton energy loss.dE/dz = -2.73 ± 0.37 GeV/fm

Charged hadron and 0 production at PHENIX versus pT for central collisions which, when compared to pQCD models that work well for peripheral collisions, suggests that jet-quenching or energy-loss may be present.

dE/dx = 0

dE/dx =0.25

Johnson, Kopeliovich et al.PRL 86, 4483 (2001)

Shadowing

dE/dx & Shadowing

Quark energy loss in nuclear matter

dE/dx = 0dE/dx =0.25

E772 DY data

Gluon Shadowing – Largely Unknown

Kopeliovich, Tarasov, & Hufnerhep-ph/0104256

Eskola, Kolhinen, Vogt hep-ph/0104124

PHENIX μ+μ- (Au)Gluon shadowing for J/Ψ’s in PHENIX μ acceptance?Large uncertainty: •Eskola… : ~ 0.8 vrs Kopeliovich… : ~ 0.4• Must be measured

PHENIX μPHENIX eE866 (Y~0)

Eskola

Kopeliovich

Shadowing for d+Au -> J/

Kopeliovich et alhep-ph/0104256& hep-ph/0205151

with anti-shadowing& EMCwithout

Shadowing more than a factor of two stronger for charmonium production than for open-charm

calculation includes absorption/formation time effects & is actually for the 2)

No EMC

Anti-shadowing

Whereas ordinary parton model shadowing factorizes and is a “property”of the nuclear structure function

Process Dependence of Shadowing Process Dependence of Shadowing

PT Broadening Raufeisen, hep-ph/0301052Relating broadening for dipole, BDMPS & higher twist

Broadening proportional to average color field strength

Raufeisen, Peng, Nayak, hep-ph/0204095

Parton model versus color dipole formulation of the Drell-Yan process

Approximate equivalence of the two approaches which are thought to represent the same physics, but in different reference frames.

E772 & E866 data

NLO (parton model)

Color dipole model