Mean-field approach in the multi-component gas of interacting particles applied to relativistic heavy-ion collisions

Abstract

A generalized mean-field approach for the thermodynamic description of relativistic single- and multi-component gas in the grand canonical ensemble is formulated. In the framework of the proposed approach, different phenomenological excluded-volume procedures are presented and compared to the existing ones. The mean-field approach is then used to effectively include hard-core repulsion in hadron-resonance gas model for description of chemical freeze-out in heavy-ion collisions. We calculate the collision energy dependence of several quantities for different values of hard-core hadron radius and for different excluded-volume procedures such as the van der Waals and Carnahan–Starling models. It is shown that a choice of the excluded-volume model becomes important for large particle densities. For large enough values of hadron radii ( fm) there can be a sizable difference between different excluded-volume procedures used to describe the chemical freeze-out in heavy-ion collisions. At the same time, for the smaller and more commonly used values of hard-core hadron radii ( fm), the precision of the van der Waals excluded-volume procedure is shown to be sufficient.