Extracting the QGP viscosity from RHIC data -- a status report from viscous hydrodynamics

Abstract

We report recent progress on causal viscous hydrodynamics for relativistic heavy ion collisions. For fixed specific shear viscosity eta/s, uncertainties in the elliptic flow arising from initial conditions, equation of state, bulk viscosity and numerical viscosity, and the treatment of the highly viscous hadronic stage and freeze-out procedure are analysed. A comparison of current viscous hydrodynamic results with experimental data yields a robust upper limit eta/s < 5/(4pi).

Comments: 8 pages, 3 figures, plenary talk at International Conference on Strangeness in Quark Matter 2008, Beijing, China, October 6-10, 2008; to appear in the proceedings published by J. Phys. G