Abstract

We present our results on the shear viscosity to entropy ratio (η/s) in the framework of the clustering of the color sources of the matter produced at RHIC and LHC energies. The onset of de-confinement transition is identified by the spanning percolating cluster in 2D percolation. The relativistic kinetic theory relation for η/s is evaluated using the initial temperature (T) and the mean free path (λmfp). The analytic expression for η/s covers a wide temperature range. At T∼150 MeV below the hadron to QGP transition temperature of ∼168 MeV, with increasing temperatures the η/s value drop sharply and reaches a broad minimum η/s∼0.20 at T∼175–185 MeV. Above this temperature η/s grows slowly. The measured values of η/s are 0.204±0.020 and 0.262±0.026 at the initial temperature of 193.6±3 MeV from central Au+Au collisions at \(\sqrt{s_{NN}}=200~\mathrm{GeV}\) (RHIC) and 262.2±13 MeV in central Pb+Pb collisions at \(\sqrt{s_{NN}} = 2.76~\mathrm{TeV}\) (LHC). These η/s values are 2.5 and 3.3 times the AdS/CFT conjectured lower bound 1/4π but are consistent with theoretical η/s estimates for a strongly coupled QGP.

Details

Title
Clustering of color sources and the shear viscosity of the QGP in heavy ion collisions at RHIC and LHC energies
Author
Dias de Deus, J 1 ; Hirsch, A S 2 ; Pajares, C 3 ; Scharenberg, R P 2 ; Srivastava, B K 2 

 CENTRA, Instituto Superior Tecnico, Lisbon, Portugal 
 Department of Physics, Purdue University, West Lafayette, IN, USA 
 Departamento de Fisica de Particulas, Universidale de Santiago de Compostela and Instituto Galego de Fisica de Atlas Enerxias (IGFAE), Santiago, de Compostela, Spain 
Pages
1-6
Publication year
2012
Publication date
Aug 2012
Publisher
Springer Nature B.V.
ISSN
14346044
e-ISSN
14346052
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2294154354
Copyright
The European Physical Journal C is a copyright of Springer, (2012). All Rights Reserved., © 2012. This work is published under https://creativecommons.org/licenses/by/2.0 (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.