Centrality, transverse momentum and collision energy dependence of the Tsallis parameters in relativistic heavy-ion collisions

Abstract

The thermodynamical properties of matter created in high-energy heavy-ion collisions have been studied in the framework of the non-extensive Tsallis statistics by fitting the transverse momentum spectra (p T ) of produced particles. The p T distributions of charged particles and identified pions from the available experimental data of Au-Au collisions at the Relativistic Heavy Ion Collider (RHIC) energies and Pb-Pb collisions at the Large Hadron Collider (LHC) energies are fitted by Tsallis distribution. The fit parameter q measures the degree of deviation of the system from an equilibrium state and T is the kinetic freezeout temperature. It is observed that, in general, q increases with the increase of collision energy and the variation with respect to centrality is collision energy dependent, whereas, T decreases with collision energy, and increases with collision centrality. A reversal of the centrality dependency has been observed for collision energies below 27 GeV. The correlation between the Tsallis parameters with centrality and collision energy are presented along with a comparison to the corresponding results from the fits of the blast-wave model.

Observation of different scenarios in different temperatures in small and large collision systems

“…The relative fractions of the particles are fixed but they still interact with each other, and then stops until the final state interactions between them are no longer effective. This stage is called thermal/kinetic freeze-out stage and the temperature at this stage is known as kinetic freezeout temperature [5][6][7][8]. In Standard model of heavy ion collisions, the kinetic freeze-out occurs after the chemical freeze-out due to large mean free path of the later which is also claimed in ref.…”

An NJL model analysis of a magnetised nonextensive QCD medium

“…On the other hand, in the pursuit of understanding the data from HIC experiments both in RHIC and LHC one statistical distribution, recently, has gained a lot of attention [11][12][13][14][15]. This is widely known as the Tsallis distribution after Constantino Tsallis who in his famous paper [16] investigated the possibility of a nonextensive form of entropy involving a parameter q.…”