Study on higher moments of net-charge multiplicity distributions using a multiphase transport model

TL;DR

This study uses a multiphase transport model to analyze net-charge multiplicity moments in heavy-ion collisions, highlighting the importance of dynamical evolution in interpreting signals related to the QCD critical point.

Contribution

It demonstrates the necessity of considering dynamical evolution when using moments of net-charge distributions to locate the QCD critical point in heavy-ion collisions.

Findings

No non-monotonic energy dependence observed in moments.

Moment products develop during dynamical evolution.

Positive two-particle correlations suggest different dynamical processes.

Abstract

The moments and moment products of conserved charges are believed to be sensitive to critical fluctuations, which have been adopted in determining the QCD critical point. Using a dynamical multiphase transport model, we reproduce the centrality and energy dependences of moments and moment products of net-charge multiplicity distributions in Au+Au collisions measured by the Beam Energy Scan program at the RHIC. No non-monotonic energy dependence is observed. We infer that the moment products develop during the dynamical evolution of heavy-ion collisions. The observed difference based on the expectation of the Poisson baseline indicates a positive two-particle correlation between positively and negatively charged particles, which can arise from different dynamical processes at different stages. Therefore, to adopt moments and moment products of net-charge multiplicity distributions in determining the QCD critical point of relativistic heavy-ion collisions, it is essential to take the dynamical evolution.