Nearly perfect fluid in Au+Au collisions at RHIC

Abstract

In the Israel-Stewart's theory of dissipative hydrodynamics, we have analysed the STAR data on $\varphi$ meson production in Au+Au collisions at $\sqrt{s}$=200 GeV. From a simultaneous fit to $\varphi$ mesons multiplicity, mean $p_T$ and integrated $v_2$, we obtain a phenomenological estimate of QGP viscosity, $\eta /s=0.07\pm 0.03\pm 0.14$, the first error is due to the experimental uncertainty in STAR measurements, the second reflects the uncertainties in initial and final conditions of the fluid.

Comments: 5 pages, 6 figures. Version accepted for publication in Phys. Lett. B