# Freeze-out temperature from net-kaon fluctuations at energies available at the BNL Relativistic Heavy Ion Collider

Bellwied, R. (Department of Physics, University of Houston, Houston, Texas 77204, USA) ; Noronha-Hostler, J. (Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA) ; Parotto, P. (Department of Physics, University of Houston, Houston, Texas 77204, USA) ; Portillo Vazquez, I. (Department of Physics, University of Houston, Houston, Texas 77204, USA) ; Ratti, C. (Department of Physics, University of Houston, Houston, Texas 77204, USA) ; Stafford, J.M. (Department of Physics, University of Houston, Houston, Texas 77204, USA)

29 March 2019

Abstract: We compare the mean-over-variance ratio of the net-kaon distribution calculated within the hadron resonance gas model to the latest experimental data from the Beam Energy Scan at the Relativistic Heavy Ion Collider by the STAR Collaboration. Our analysis indicates that it is not possible to reproduce the experimental results using the freeze-out parameters from the existing combined fit of net-proton and net-electric charge mean over variance. The strange mesons need about 15 MeV higher temperatures than the light hadrons at the highest collision energies. In view of the future $\Lambda$ fluctuation measurements, we predict the $\Lambda$ variance over mean and skewness times variance at the light and strange chemical freeze-out parameters. We observe that the $\Lambda$ fluctuations are sensitive to the difference in the freeze-out temperatures established in this analysis. Our results have implications for other phenomenological models in the field of relativistic heavy ion collisions.

Published in: Physical Review C 99 (2019)