Energy dependence of jet transport parameter and parton saturation in quark-gluon plasma

Journal Article · Fri Feb 15 04:00:00 EST 2008 · Physical Review. C, Nuclear Physics

DOI:https://doi.org/10.1103/PHYSREVC.77.024902· OSTI ID:21068138

Casalderrey-Solana, Jorge; Xinnian, Wang ^[1]

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1. Nuclear Science Division, MS 70R0319, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

We study the evolution and saturation of the gluon distribution function in the quark-gluon plasma as probed by a propagating parton and its effect on the computation of jet quenching or transport parameter q-circumflex. For thermal partons, the saturation scale Q{sub s}{sup 2} is found to be proportional to the Debye screening mass {mu}{sub D}{sup 2}. For hard probes, evolution at small x=Q{sub s}{sup 2}/6ET leads to jet energy dependence of q-circumflex. We study this dependence both for a conformal gauge theory in weak and strong coupling limit and for (pure gluon) QCD. The energy dependence can be used to extract the shear viscosity {eta} of the medium, since {eta} can be related to the transport parameter for thermal partons in a transport description. We also derive upper bounds on the transport parameter for both energetic and thermal partons. The latter leads to a lower bound on the shear viscosity to entropy density ratio which is consistent with the conjectured lower bound {eta}/s{>=}1/4{pi}. We also discuss the implications of these results on the study of jet quenching at the BNL Relativistic Heavy Ion Collider and the CERN Large Hadron Collider and the bulk properties of the dense matter.

• OSTI ID: 21068138
• Journal Information: Physical Review. C, Nuclear Physics, Journal Name: Physical Review. C, Nuclear Physics Journal Issue: 2 Vol. 77; ISSN 0556-2813; ISSN PRVCAN
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
BROOKHAVEN RHIC
CALCULATION METHODS
CERN LHC
DENSITY
DISTRIBUTION FUNCTIONS
ENERGY DEPENDENCE
ENTROPY
GAUGE INVARIANCE
GLUONS
HEAVY ION REACTIONS
JET MODEL
MASS
QUANTUM CHROMODYNAMICS
QUARK MATTER
QUARKS
QUENCHING
RADIATION TRANSPORT
SHEAR
STRONG-COUPLING MODEL
VISCOSITY