Nearly perfect fluid in Au + Au collisions at RHIC

In the Israel-Stewart's theory of dissipative hydrodynamics, we have analysed the STAR data on ϕ meson production in Au + Au collisions at s=200 GeV. From a simultaneous fit to ϕ mesons multiplicity, mean pT and integrated v2, we obtain a phenomenological estimate of QGP viscosity, η/s=0.07±0.03±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.