# Energy dependence of jet transport parameter and parton saturationin quark-gluon plasma

### Description

We study the evolution and saturation of the gluondistribution function in the quark-gluon plasma as probed by apropagating parton and its effect on the computation of jet quenching ortransport parameter $\hat q$. For thermal partons, the saturation scale$Q2_s$ is found to be proportional to the Debye screening mass $\mu_D2$.For hard probes, evolution at small $x=Q2_s/6ET$ leads to jet energydependence of hat q. We study this dependence for both a conformal gaugetheory in weak and strong coupling limit and for (pure gluon) QCD. Theenergy dependence can be used to extract the shear viscosity $\eta$ ofthe medium since $\eta$ can be ... continued below

### Creation Information

Casalderrey-Solana, Jorge & Wang, Xin-Nian June 24, 2007.

## Who

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## What

### Description

We study the evolution and saturation of the gluondistribution function in the quark-gluon plasma as probed by apropagating parton and its effect on the computation of jet quenching ortransport parameter $\hat q$. For thermal partons, the saturation scale$Q2_s$ is found to be proportional to the Debye screening mass $\mu_D2$.For hard probes, evolution at small $x=Q2_s/6ET$ leads to jet energydependence of hat q. We study this dependence for both a conformal gaugetheory in weak and strong coupling limit and for (pure gluon) QCD. Theenergy dependence can be used to extract the shear viscosity $\eta$ ofthe medium since $\eta$ can be related to the transport parameter forthermal partons in a transport description. We also derive upper boundson the transport parameter for both energetic and thermal partons. Thelater leads to a lower bound on shear viscosity-to-entropy density ratiowhich is consistent with the conjectured lower bound $\eta/s\geq 1/4\pi$.Implications on the study of jet quenching at RHIC and LHC and the bulkproperties of the dense matter are discussed.

### Source

• Journal Name: Physical Review C; Journal Volume: 0; Journal Issue: 0; Related Information: Journal Publication Date: 0

### Identifier

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• Report No.: LBNL--63308
• Grant Number: DE-AC02-05CH11231
• Office of Scientific & Technical Information Report Number: 929024

### Collections

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## When

### Creation Date

• June 24, 2007

### Added to The UNT Digital Library

• Sept. 27, 2016, 1:39 a.m.

### Description Last Updated

• Sept. 30, 2016, 2:24 p.m.

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