Cumulants of net-strangeness multiplicity distributions at energies available at the BNL Relativistic Heavy Ion Collider

TL;DR

This paper investigates the higher-order cumulants of net-strangeness multiplicity distributions in heavy-ion collisions, using models to understand fluctuations and resonance decay effects, aiding the search for the QCD critical point.

Contribution

It introduces a detailed analysis of net-strangeness cumulants using the UrQMD model and HRG calculations, emphasizing the importance of resonance decay contributions for accurate results.

Findings

Resonance decays significantly affect net-strangeness cumulants.

Proxies like kaons and lambdas effectively represent strangeness fluctuations.

Model calculations help interpret experimental fluctuation measurements.

Abstract

The higher-order cumulants of net-proton number, net-charge, and net-strangeness multiplicity distributions are widely studied to search for the quantum-chromodynamics critical point and extract the chemical freeze-out parameters in heavy-ion collisions. In this context, the event-by-event fluctuations of the net-strangeness multiplicity distributions play important roles in extracting the chemical freeze-out parameter in the strangeness sector. Due to having difficulties in detecting all strange hadrons event by event, the kaon ($K$) and lambda ($\Lambda$) particles serve as a proxy for the strangeness-related observables in heavy-ion collisions. We have studied the net-$K$, net-$\Lambda$, and net-($K$ + $\Lambda$) multiplicity distributions and calculated their different order of cumulants using the ultrarelativistic quantum molecular dynamics model and hadron resonance gas calculation. To adequately account for the net-strangeness cumulants, it has been found that the inclusion of resonance decay contributions in $K$ and $\Lambda$ is necessary.