200 A GeV Au+Au collisions serve a nearly perfect quark-gluon liquid

2010/11/30 by Huichao Song, Steffen A. Bass, Ulrich W. Heinz +2 · 1 citation
Physics and Astronomy · #nucl-th #hep-ph #nucl-ex

paper · pdf · doi:10.1103/physrevlett.106.192301

published as Phys.Rev.Lett.106:192301,2011 · 4 pages, 2 figures, accepted by PRL

arxiv created 2011/04/21 · arxiv updated 2011/05/23

Abstract

The specific shear viscosity (eta/s)_QGP of a Quark-Gluon-Plasma (QGP) at temperatures T_c < T < 2T_c is extracted from the centrality dependence of the eccentricity-scaled elliptic flow measured in ultra-relativistic heavy-ion collisions. Coupling viscous fluid dynamics for the QGP with a microscopic transport model for hadronic freeze-out we find that the eccentricity-scaled elliptic flow is a universal function of charged multiplicity per unit overlap area, (1/S)(dN_ch/dy), that depends only on the viscosity but not on the model used for computing the initial fireball eccentricity. Comparing with measurements we find 1 < (4pi)(eta/s)_QGP < 2.5 where the uncertainty range is dominated by model uncertainties for the eccentricity values used to normalize the measured elliptic flow.

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