Study of Centrality Dependence of Kinetic Freeze-out Conditions in Pb + Pb Collisions at Root(sNN)= 2.76 TeV

TL;DR

This study analyzes how kinetic freeze-out conditions vary with collision centrality in Pb+Pb collisions at 2.76 TeV, using a thermal model to fit transverse momentum spectra and extract temperature and flow parameters.

Contribution

It introduces a unified thermal freeze-out model that accounts for both longitudinal and transverse flows to interpret experimental spectra at LHC energies.

Findings

Freeze-out temperature increases from peripheral to central collisions.

Collective flow velocity mildly decreases from central to peripheral collisions.

Model results agree well with ALICE experimental data.

Abstract

The transverse momentum spectra of identified particles at midrapidity in Pb + Pb collisions at Root(sNN) = 2.76 TeV have been studied as a function of collision centrality by using a unified statistical thermal freeze-out model. The calculated results are found to be in good agreement with the experimental data measured by the ALICE experiment at LHC. The model calculations provide the thermal freeze-out conditions in terms of the temperature and collective flow parameters for different particle species. We observe a rise in the thermal freeze-out temperature but a mild decrease in the collective flow velocity parameter from central to peripheral collisions. The model used incorporates the simultaneous effect of the longitudinal as well as transverse hydrodynamic flows. The baryon chemical potential is assumed to be zero ({\mu}B ~ 0), a situation expected in the heavy ion collisions at LHC energies due to a high degree of nuclear transparency.