# Quark Matter 2014 - XXIV International Conference on Ultrarelativistic Nucleus-Nucleus Collisions

19-24 May 2014
Europe/Zurich timezone

## Shear viscosity from a large-$N_c$ NJL model at next-to-leading order

20 May 2014, 16:30
2h

### spectrum

Board: A-13
Poster QCD at High Temperature and/or Density

### Speaker

Mr Robert Lang (TUM, RIKEN)

### Description

Heavy-ion collisions at RHIC and LHC suggest that the shear viscosity to entropy ratio, $\eta/s$, is close to the AdS/CFT benchmark $1/4\pi$ indicating a strongly correlated state of matter produced in such collisions. The ratio $\eta/s$ is investigated in the vicinity of the chiral crossover using the two-flavor NJL model in a large-$N_c$ expansion. We study the non-perturbative structure of the NJL model and compare our approach to others such as kinetic theory. The issue of ladder resummation in the Kubo formalism and its relationship to the perturbative treatment of the model is examined. Dissipative contributions at next-to-leading-order to the shear viscosity lead to a pronounced minimum of $\eta/s$ above the AdS/CFT benchmark.
On behalf of collaboration: None

### Primary author

Mr Robert Lang (TUM, RIKEN)

### Co-authors

Prof. Tetsuo Hatsuda (RIKEN) Prof. Wolfram Weise (ECT*, TUM)

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