Kinetic freeze out conditions in nuclear collisions with $2A$ - $158A$ GeV beam energy within a non-boost-invariant blast-wave model

TL;DR

This paper analyzes the kinetic freeze-out conditions of bulk hadrons in nuclear collisions across a wide energy range using a non-boost-invariant blast wave model, providing insights into collision dynamics relevant for future experiments.

Contribution

It introduces a generalized non boost-invariant blast wave model to study freeze-out conditions across a broad energy spectrum in nuclear collisions.

Findings

Kinetic freeze-out temperature ranges from 55 to 90 MeV.

Average transverse velocity of expansion is about 0.5c to 0.6c.

Longitudinal velocity increases monotonically with boost.

Abstract

We study the kinetic freeze out conditions of bulk hadrons in nuclear collisions. The transverse and longitudinal momentum spectra of the identified hadrons produced in central Au+Au and Pb+Pb collisions, in the beam energy range of $E_b = 2A - 158 A$ GeV are analysed for this purpose, within a generalised non boost-invariant blast wave model. The kinetic freeze out temperature is found to vary in the range of 55 - 90 MeV, whereas the average transverse velocity of collective expansion is found to be around $0.5c$ to $0.6c$. The mean longitudinal velocity of the fireball is seen to increase monotonically with increasing longitudinal boost. The results would be useful to understand the gross collision dynamics for the upcoming experiments at the FAIR and NICA accelerator facilities.