Cumulants of net-strangeness multiplicity distributions at RHIC energies

The higher order cumulants of net-proton number, net-charge, and net-strangeness multiplicity distributions are widely studied to search for the Quantum-Chromodynamics(QCD) critical point and extract the chemical freeze-out parameters in heavy-ion collisions. In this context, the event-by-event fluctuations of the net-strangeness multiplicity distributions play important roles in extracting the chemical freeze-out parameter in the strangeness sector. Due to having difficulties in detecting all strange hadrons event-by-event, the kaon (K) and lambda($\Lambda$) particles serve as a proxy for the strangeness related observable in heavy-ion collisions. We have studied the net-K, net-$\Lambda$, and net-(Kaon + $\Lambda$) multiplicity distributions and calculated their different order of cumulants using the UrQMD model and Hadron Resonance Gas (HRG) calculation. It is found that resonance decay contributes to the net-strangeness cumulants. Furthermore, we compare the freeze-out parameters used in the HRG calculation to match the STAR published net-kaon and net-lambda higher order cumulants data with that extracted from the strange particle yield data and find consistency between these two methods.