Fluid properties of hadron gas produced in relativistic hadronic and heavy-ion collisions

Abstract

Thermalization is a vital feature that enables the study of hydrodynamic evolution of the medium produced in nuclear collisions at relativistic energies. Here, we obtain the variation of Knudsen number (Kn) to study the degree of thermalization in an excluded volume hadron resonance gas model. Kn along with other parameters like Reynolds number (Re) and Mach number (Ma) give insights into the nature of the flow in a system. The dependence of these dimensionless parameters on system size and baryonic chemical potential (µB) are studied. The obtained values of the parameters (Kn &lt

&lt

1, Ma ∼ 1 and Re &gt

&gt

1) indicate the occurrence of compressible inviscid flows at high temperatures close to the QCD phase transition region (T ∼ 150−170 MeV). The degree of thermalization of hadron gas estimated is comparable over different system sizes, indicating the applicability of hydrodynamics in interpreting the results from high multiplicity pp to heavy-ion collisions. © Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND 4.0).