Correlation functions of net-proton multiplicity distributions in Au + Au collisions at energies available at the BNL Relativistic Heavy Ion Collider from a multiphase transport model

TL;DR

This study investigates the behavior of correlation functions of net-proton multiplicity distributions in heavy-ion collisions at various energies using the AMPT model, aiming to understand signals related to the QCD phase transition.

Contribution

It provides a detailed analysis of net-proton correlation functions across energies and centralities using the AMPT model, highlighting the importance of antiprotons in these correlations.

Findings

Antiprotons significantly influence correlation functions at high energies.

Higher order correlations are more affected by antiprotons than lower ones.

Model results align with experimental data from STAR at RHIC.

Abstract

Fluctuations of conserved quantities are believed to be sensitive observables to probe the signature of the QCD phase transition and critical point. It was argued recently that measuring the genuine correlation functions (CFs) could provide cleaner information on possible nontrivial dynamics in heavy-ion collisions.With the AMPT (a multiphase transport) model, the centrality and energy dependence of various orders of CFs of net protons in Au + Au collisions at $\sqrt{s_\mathrm{NN}}$=7.7, 11.5, 19.6, 27, 39, 62.4 and 200 GeV are investigated. The model results show that the number of antiprotons is important and should be taken into account in the calculation of CFs at high energy and/or in peripheral collisions. It is also found that the contribution of antiprotons is more important for higher order correlations than for lower ones. The CFs of antiprotons and mixed correlations play roles comparable to those of protons at high energies. Finally, we make comparisons between the model calculation and experimental data measured in the STAR experiment at the BNL Relativistic Heavy Ion Collider.