Di-hadron azimuthal correlation and Mach-like cone structure in a parton/hadron transport model

In the framework of a multi-phase transport model (AMPT) with both partonic and hadronic interactions, azimuthal correlations between trigger particles and associated scattering particles have been studied by the mixing-event technique. The momentum ranges of these particles are 3 < p(T)(trig) < 6 GeV/c and 0. 15 < pa(T)(assoc) < 3 GeV/c (soft), or 2.5 < p(T)(trig) < 4 GeV/c and 1 < p(T)(assoc) < 2.5 GeV/c (hard)in An + Au collisions at root s(NN) = 200 GeV. A Mach-like structure has been observed in correlation functions for central collisions. By comparing scenarios with and without parton cascade and hadronic rescattering, we show that both partonic and hadronic dynamical mechanisms contribute to the Mach-like structure of the associated particle azimuthal correlations. The contribution of hadronic dynamical process cannot be ignored in the emergence of Mach-like correlations of the soft scattered associated hadrons. However, hadronic rescattering alone cannot reproduce experimental amplitude of Mach-like cone on away-side, and the Parton cascade process is essential to describe experimental amplitude of Mach-like cone on away-side. In addition, both the associated multiplicity and the sum Of PT decrease, while the < PT > increases, with the impact parameter in the AMPT model including partonic dynamics from string melting scenario. (c) 2006 Elsevier B.V. All rights reserved.