Jet quenching by (pre--)hadronic final state interactions at RHIC

Abstract

Within a hadron-string dynamical transport approach (HSD) we investigate the attenuation of high transverse momentum ($\pT$) hadrons as well as the suppression of 'near-side' and 'far-side' jets in $Au+Au$ collisions at invariant energies $\sqrt{s}$ = 200 GeV and $\sqrt{s}$ = 62.4 GeV in comparison to the data available from the Relativistic Heavy-Ion Collider (RHIC). From our transport studies we find that a significant part of the high $\pT$ hadron attenuation seen experimentally can be attributed to inelastic interactions of 'leading' pre-hadrons with the dense hadronic environment. In addition, we also show results of 'near-side' and 'far-side' angular correlations of high $\pT$ particles from Au+Au collisions at $\sqrt{s}$ = 200 GeV and $\sqrt{s}$ = 62.4 GeV within this (pre-)hadronic attenuation scenario. It turns out that the 'near-side' correlations are unaltered -- in accordance with experiment -- whereas the 'far-side' correlations are suppressed by up to $\sim$ 60% in central collisions. Since a much larger suppression is observed experimentally for these reactions in central reactions we conclude that there should be strong additional (and earlier) partonic interactions in the dense and possibly colored medium created in Au+Au collisions at RHIC.