Baryon-Strangeness Correlations in Au+Au Collisions at $\sqrt{s_\mathrm{NN}}$=7.7-200 GeV from the UrQMD model

TL;DR

This study uses the UrQMD model to analyze baryon-strangeness correlations in Au+Au collisions across a range of energies, providing baseline data for QCD phase transition and critical point searches.

Contribution

It offers a comprehensive analysis of mixed-cumulants of net-baryon and net-strangeness, comparing UrQMD results with lattice QCD and HRG models, and explores energy and centrality dependence.

Findings

Mixed-cumulant ratios show weak centrality dependence.

Strong increase of certain ratios at low energies.

Results align with lattice QCD and HRG model predictions.

Abstract

Fluctuations and correlations of conserved charges are sensitive observables for studying the QCD phase transition and critical point in high-energy heavy-ion collisions. We have studied the centrality and energy dependence of mixed-cumulants (up to fourth order) between net-baryon and net-strangeness in Au+Au collisions at $\sqrt{s_{NN}}$= 7.7, 11.5, 19.6, 27, 39, 62.4, 200 GeV from UrQMD model. To compare with other theoretical calculations, we normalize these mixed-cumulants by various order cumulants of net-strangeness distributions. We found that the results obtained from UrQMD calculations are comparable with the results from Lattice QCD at low temperature and hadron resonance gas model. The ratios of mixed-cumulants ($R_{11}^{BS},R_{13}^{BS},R_{22}^{BS}$,~$R_{31}^{BS}$) from UrQMD calculations show weak centrality dependence. However, the mixed-cumulant ratios $R_{11}^{BS}$ and $R_{31}^{BS}$ show strong increase at low energy, while the $R_{13}^{BS}$ snd $R_{22}^{BS}$ are similar at different energies. Furthermore, we have also studied the correlations between different hadron species and their contributions to the net-baryon and net-strangeness correlations. These models studies can provide baselines for searching for the signals of QCD phase transition and critical point in heavy-ion collisions.