Dissipative effects from transport and viscous hydrodynamics

We compare 2 -> 2 covariant transport theory and causal Israel-Stewart hydrodynamics in a (2+1)-dimensional longitudinally boost-invariant geometry with RHIC-like initial conditions and a conformal epsilon = 3p equation of state. The pressure evolution in the center of the collision zone and the final differential elliptic flow nu(2)(p(T)) from the two theories agree remarkably well for a small shear viscosity to entropy density ratio eta/s approximate to 1/(4 pi), and also for a large cross section sigma approximate to 50 mb. A key to this agreement is keeping all terms in the Israel Stewart equations of motion. Our results indicate promising prospects for the applicability of Israel-Stewart dissipative hydrodynamics at RHIC, provided the shear viscosity of hot and dense quark-gluon matter is indeed very small for the relevant temperatures T similar to 200-500 MeV.