Thermodynamic Parameters at Kinetic Freeze-out in Relativistic Heavy-Ion Collisions Using Tsallis Statistics

Thermodynamic properties of the hot and dense system produced in relativistic heavy-ion collisions have been studied by analyzing the transverse momentum (pT) spectra of emitted particles (pions, kaons, and protons). The spectra are fitted using the non-extensive Tsallis statistics. The fit parameters, q and T , provide the degree of deviation of the system from an equilibrium state and the effective temperature at freeze-out, respectively. These parameters are presented as a function of collision energy, collision centrality, and different fit ranges in pT for available experimental data at Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC) energies. An anti-correlation between the two fit parameters has been observed. With the increase of the collision energy, q increases in a systematic manner whereas T has a decreasing trend. For central collisions, q and T have a strong dependence on the fitting ranges of pT, however, for peripheral collisions there is a minor dependency on pT. The Tsallis parameters are found to have mass ordering, which needs further investigation with the inclusion of radial flow.