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

摘要

Fluctuations and correlations of conserved charges are sensitive observablesfor studying the QCD phase transition and critical point in high-energyheavy-ion collisions. We have studied the centrality and energy dependence ofmixed-cumulants (up to fourth order) between net-baryon and net-strangeness inAu+Au collisions at $\sqrt{s_{NN}}$= 7.7, 11.5, 19.6, 27, 39, 62.4, 200 GeVfrom UrQMD model. To compare with other theoretical calculations, we normalizethese mixed-cumulants by various order cumulants of net-strangenessdistributions. We found that the results obtained from UrQMD calculations arecomparable with the results from Lattice QCD at low temperature and hadronresonance gas model. The ratios of mixed-cumulants($R_{11}^{BS},R_{13}^{BS},R_{22}^{BS}$,~$R_{31}^{BS}$) from UrQMD calculationsshow 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 andtheir contributions to the net-baryon and net-strangeness correlations. Thesemodels studies can provide baselines for searching for the signals of QCD phasetransition and critical point in heavy-ion collisions.