# Off-diagonal cumulants of net-charge, net-proton and net-kaon multiplicity distributions in Au+Au collisions at $\sqrt{s_{NN}}$ = 7.7-200 GeV from STAR

## TL;DR

This paper reports on STAR measurements of second-order off-diagonal cumulants of net-charge, net-proton, and net-kaon multiplicity distributions in Au+Au collisions across a range of energies, providing insights into QCD matter properties.

## Contribution

It presents the first experimental measurements of off-diagonal cumulants in heavy-ion collisions and compares them with theoretical models to constrain the QCD phase diagram.

## Key findings

- Measured cumulant ratios show agreement with HRG and UrQMD models.
- Results help constrain freeze-out parameters in the QCD phase diagram.
- Data across energies reveal trends in conserved charge fluctuations.

## Abstract

Fluctuations of conserved quantities such as net-baryon, net-charge, and net-strangeness numbers have generated considerable interest in the study of the thermodynamic properties of the hot and dense QCD matter. Theoretical calculations suggest that the off-diagonal cumulants of conserved charges along with the diagonal cumulants can help better constrain the freeze-out parameters and, therefore, help to map the QCD phase diagram. In this proceeding, we briefly outline the recent STAR measurements on the second-order off-diagonal cumulants of net-charge, net-proton, and net-kaon multiplicity distributions in Au+Au collisions from the RHIC BES-I program in the energy range of $\sqrt{s_{NN}}$ = 7.7-200 GeV. The measured cumulant ratios are compared to the predictions from both thermal (HRG) and non-thermal (UrQMD) models.