Indication of Differential Kinetic Freeze-out at RHIC and LHC Energies

TL;DR

This study analyzes transverse momentum spectra at RHIC and LHC using Tsallis distributions, revealing mass-dependent differential freeze-out and similar thermodynamic properties in different collision systems.

Contribution

It provides new insights into mass-dependent freeze-out surfaces and radial flow velocities, highlighting differential freeze-out signatures at different energies and collision types.

Findings

Heavier particles freeze out earlier than lighter ones.

Radial flow velocity decreases with increasing particle mass.

Peripheral heavy-ion and proton-proton collisions exhibit similar thermodynamic behavior.

Abstract

The transverse momentum spectra at RHIC and LHC for A+A and p+p collisions are studied with Tsallis distributions in different approaches i.e. with and without radial flow. The information on the freeze-out surface in terms of freeze-out volume, temperature, chemical potential and radial flow velocities for different particle species are obtained. These parameters are found to show a systematic behavior with mass dependence. It is observed that the heavier particles freeze-out early as compared to lighter particles and freeze-out surfaces are different for different particles, which is a direct signature of mass dependent differential freeze-out. Further, we observe that the radial flow velocity decreases with increasing mass. This confirms the mass ordering behavior in collectivity observed in heavy-ion collisions. It is also observed that the systems created in peripheral heavy-ion collisions and in proton-proton collisions are of similar thermodynamic nature.