Collision Energy Dependence of Moments of Net-Kaon Multiplicity Distributions at RHIC

TL;DR

This paper presents the first measurements of net-kaon multiplicity moments across various collision energies at RHIC, providing insights into fluctuations related to the QCD critical point.

Contribution

It introduces novel measurements of net-kaon moments at multiple energies, offering data to explore QCD critical phenomena in heavy-ion collisions.

Findings

Net-kaon cumulant ratios are monotonic with collision energy.

Results are consistent with baseline models within current uncertainties.

Provides new experimental data for QCD critical point searches.

Abstract

Fluctuations of conserved quantities such as baryon number, charge, and strangeness are sensitive to the correlation length of the hot and dense matter created in relativistic heavy-ion collisions and can be used to search for the QCD critical point. We report the first measurements of the moments of net-kaon multiplicity distributions in Au+Au collisions at $\sqrt{s_{\rm NN}}$ = 7.7, 11.5, 14.5, 19.6, 27, 39, 62.4, and 200 GeV. The collision centrality and energy dependence of the mean ($M$), variance ($\sigma^2$), skewness ($S$), and kurtosis ($\kappa$) for net-kaon multiplicity distributions as well as the ratio $\sigma^2/M$ and the products $S\sigma$ and $\kappa\sigma^2$ are presented. Comparisons are made with Poisson and negative binomial baseline calculations as well as with UrQMD, a transport model (UrQMD) that does not include effects from the QCD critical point. Within current uncertainties, the net-kaon cumulant ratios appear to be monotonic as a function of collision energy.