Constraining the particle production mechanism in Au+Au collisions at sNN =7.7, 27, and 200 GeV using a multiphase transport model

Abstract

We study the production of pions, kaons, and (anti)protons using a multiphase transport (AMPT) model in Au+Au collisions at sNN= 7.7, 27, and 200 GeV. We present the centrality and energy dependence of various bulk observables such as invariant yields as a function of transverse momentum pT, particle yields dN/dy, average transverse momentum (pT), and various particle ratios, and compare them with experimental data. Both default and string melting (SM) versions of the AMPT model are used with three different sets of initial conditions. We observe that neither the default nor the SM version of the model could consistently describe the centrality dependence of all observables at the above energies with any one set of initial conditions. The energy dependence behavior of the experimental observables for 0-5% central collisions is in general better described by the default AMPT model using the modified hijing parameters for Lund string fragmentation and 3 mb parton scattering cross section. In addition, the kaon production as well as the K/π ratio at 7.7 GeV are underpredicted by the AMPT model.