Transverse Energy Evolution as a Test of Parton Cascade Models

Abstract

We propose a test of Monte Carlo Parton Cascade models based on analytic solutions of covariant kinetic theory for longitudinally boost and transverse translation invariant boundary conditions. We compute the evolution of the transverse energy per unit rapidity for typical mini-jet initial conditions expected in ultra-relativistic nuclear collisions. The kinetic theory solutions under these conditions test the models severely because they deviate strongly from free-streaming and also from ideal Euler and dissipative Navier-Stokes hydrodynamical approximations. We show that the newly formulated ZPC model passes this test. In addition, we show that the initial mini-jet density would need to be approximately four times higher than estimated with the HIJING generator in central Au+Au collisions at c.m. energies 200 AGeV in order that parton cascade dynamics can be approximated by Navier-Stokes hydrodynamics.