Effect of correlations on cumulants in heavy-ion collisions

TL;DR

This paper investigates how correlations influence cumulants in net-proton distributions from heavy-ion collisions, revealing that measured cumulants follow independent production models despite underlying correlations, with implications for interpreting collision data.

Contribution

The study demonstrates the impact of correlations on cumulants and their ratios in net-proton distributions, using both theoretical models and HIJING simulations.

Findings

Correlations significantly affect cumulants and their ratios.

Measured cumulants follow independent production models despite correlations.

HIJING simulations support the theoretical findings.

Abstract

We study the effects of correlations on cumulants and their ratios of net-proton multiplicity distributions which have been measured for central (0\%-5\%) Au + Au collisions at the Relativistic Heavy Ion Collider (RHIC). This effect has been studied assuming individual proton and anti-proton distributions as a Poisson or Negative Binomial Distribution (NBD). In-spite of significantly correlated production due to baryon number, electric charge conservation and kinematical correlations of protons and anti-protons, the measured cumulants of the net-proton distribution follow the independent production model. In the present work we demonstrate how the introduction of the correlations will affect the cumulants and their ratios for the difference distributions. We have also demonstrated this study using the proton and anti-proton distributions obtained from the HIJING event generator.