Centrality dependence of elliptic flow, the hydrodynamic limit, and the viscosity of hot QCD

Journal Article · Wed Aug 15 04:00:00 EDT 2007 · Physical Review. C, Nuclear Physics

DOI:https://doi.org/10.1103/PHYSREVC.76.024905· OSTI ID:21061979

Drescher, Hans-Joachim ^[1]; Dumitru, Adrian ^[2]; Gombeaud, Clement; Ollitrault, Jean-Yves ^[3]

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1. Frankfurt Institute for Advanced Studies (FIAS), Johann Wolfgang Goethe-Universitaet, Max-von-Laue-Str. 1, D-60438 Frankfurt am Main (Germany)
2. Institut fuer Theoretische Physik, Johann Wolfgang Goethe-Universitaet, Max-von-Laue-Str. 1, D-60438 Frankfurt am Main (Germany)
3. Service de Physique Theorique, CEA/DSM/SPhT, CNRS/MPPU/URA2306 CEA Saclay, F-91191 Gif-sur-Yvette Cedex (France)

We show that the centrality and system-size dependence of elliptic flow measured at the BNL Relativistic Heavy Ion Collider (RHIC) are fully described by a simple model based on eccentricity scaling and incomplete thermalization. We argue that the elliptic flow is at least 25% below the (ideal) ''hydrodynamic limit,'' even for the most central Au-Au collisions. This lack of perfect equilibration allows for estimates of the effective parton cross section in the quark-gluon plasma and of its viscosity to entropy density ratio. We also show how the initial conditions affect the transport coefficients and thermodynamic quantities extracted from the data, in particular, the viscosity and the speed of sound.

• OSTI ID: 21061979
• Journal Information: Physical Review. C, Nuclear Physics, Journal Name: Physical Review. C, Nuclear Physics Journal Issue: 2 Vol. 76; ISSN 0556-2813; ISSN PRVCAN
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
BROOKHAVEN RHIC
CROSS SECTIONS
DENSITY
ENTROPY
GOLD 197 REACTIONS
GOLD 197 TARGET
HYDRODYNAMIC MODEL
QUANTUM CHROMODYNAMICS
QUARK MATTER
SOUND WAVES
THERMALIZATION
THERMODYNAMICS
VISCOSITY