Importance of granular structure in the initial conditions for the elliptic flow.

ABSTRACT

We show the effects of the granular structure of the initial conditions of a hydrodynamic description of high-energy nucleus-nucleus collisions on some observables, especially on the elliptic-flow parameter v2. Such a structure enhances production of isotropically distributed high-pT particles, making v2 smaller there. Also, it reduces v2 in the forward and backward regions where the global matter density is smaller and, therefore, where such effects become more efficacious.