# Hard Probe 2016

22-27 September 2016
East Lake International Conference Center
Asia/Chongqing timezone
<a href="http://hp2016.ccnu.edu.cn">http://hp2016.ccnu.edu.cn</a>

## Transport coefficients from energy loss studies in an expanding QGP

25 Sep 2016, 08:50
20m
Xiang-Yang Hall (East Lake International Conference Center)

### Xiang-Yang Hall

#### East Lake International Conference Center

Donghu Road 142, Wuchang District, Wuhan, Hubei, China

### Speaker

Alejandro Ayala (UNAM)

### Description

Based on:

"Relating $\hat{q}$, $\eta/s$ and $\Delta E$ in an expanding Quark-Gluon Plasma"
A. Ayala, I. Dominguez, J. Jalilian-Marian and M. E. Tejeda-Yeomans
e-Print: arXiv:1603.09296 [hep-ph]
submitted to Phys. Rev. C

### Summary

We present a study where we explore the connection between transport coefficients and the description of in-medium energy loss within a linear viscous hydrodynamical evolution of the bulk. We use linear viscous hydrodynamics to describe the energy and momentum deposited by a fast moving parton in a quark gluon plasma. This energy-momentum is in turn used to compute the probability density for the production of soft partons by means of the Cooper-Frye formula. We use this probability density to render manifest a relation between the average transverse momentum given to the fast moving parton from the medium $\hat{q}$, the shear viscosity to entropy density ratio $\eta/s$ and the energy lost by the fast moving parton $\Delta E$ in an expanding medium under similar conditions to those generated in nucleus-nucleus collisions at the LHC. We find that $\eta/s$ has a non-trivial path length and trigger energy loss dependence, it reaches a limiting value as a function of $\hat{q}$. We will show that $\eta/s$ can be extracted in a more reliable manner for events where the trigger particle
has lost a large amount of energy and for events with a larger eccentricity. Our findings also indicate that the extraction of reliable values of $\eta/s$, can be better achieved by looking at events with an energetic jet.

Presentation type Oral