Constraining the Particle Production Mechanism in Au+Au Collisions at $\sqrt{s_{NN}}=$ 7.7, 27, and 200 GeV Using A Multi Phase Transport Model

TL;DR

This study evaluates the ability of the AMPT model to reproduce particle production in Au+Au collisions at various energies, highlighting limitations and the impact of different initial conditions and model versions.

Contribution

It provides a systematic comparison of default and string melting AMPT models with experimental data across multiple energies and centralities, identifying their strengths and shortcomings.

Findings

Default AMPT with modified parameters better describes energy dependence.

Neither model version fully captures all observables' centrality dependence.

Kaon production and K/π ratio at 7.7 GeV are underpredicted.

Abstract

We study the production of pions, kaons, and (anti)protons in A Multi Phase Transport (AMPT) Model in Au+Au collisions at $\sqrt{s_{NN}}=$ 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 $p_T$, particle yields $dN/dy$, average transverse momentum $\langle p_T \rangle$, 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 3mb parton scattering cross-section. In addition, the kaon production as well as the $K/\pi$ ratio at 7.7 GeV are under predicted by the AMPT model.