Abstract
We estimate chemical freeze-out parameters in Hadron Resonance Gas (HRG) and Excluded Volume HRG (EVHRG) models by fitting the experimental information of net-proton and net-charge fluctuations measured in Au + Au collisions by the STAR Collaboration at the BNL Relativistic Heavy Ion Collider (RHIC). We observe that chemical freeze-out parameters obtained from lower and higher order fluctuations are almost the same for GeV, but tend to deviate from each other at lower . Moreover, these separations increase with decrease of , and for a fixed increase towards central collisions. Furthermore, we observe an approximate scaling behavior of with for the parameters estimated from lower order fluctuations for GeV. Scaling is violated for the parameters estimated from higher order fluctuations for and 19.6 GeV. It is observed that the chemical freeze-out parameter, which can describe of net protons very well in all energies and centralities, cannot describe the equally well, and vice versa.
- Received 20 September 2016
- Revised 26 April 2017
DOI:https://doi.org/10.1103/PhysRevC.96.014902
©2017 American Physical Society