Cumulants of event-by-event net-strangeness distributions in Au + Au collisions at sNN=7.7–200 GeV within an UrQMD model
AbstractFluctuations of conserved quantities, such as baryon, electric charge, and strangeness number, are sensitive observables in heavy-ion collisions to search for the QCD phase transition and critical point. In this paper, we performed a systematical analysis on the various cumulants and cumulant ratios of event-by-event net-strangeness distributions in Au+Au collisions at sNN=7.7, 11.5, 19.6, 27, 39, 62.4, and 200 GeV from an ultrarelativistic quantum molecular dynamics model. We performed a systematical study on the contributions from various strange baryons and mesons to the net-strangeness fluctuations. The results demonstrate that the cumulants and cumulant ratios of net-strangeness distributions extracted from different strange particles show very different centrality and energy-dependence behavior. By comparing with the net-kaon fluctuations, we found that the strange baryons play an important role in the fluctuations of net strangeness. This study can provide useful baselines to study the QCD phase transition and search for the QCD critical point by using the fluctuations of net strangeness in heavy-ion collisions experiment. It can help us to understand noncritical physics contributions to the fluctuations of net strangeness.