Study of the particle transverse momentum spectra in relativistic heavy ion collisions using the Tsallis statistics

Oana Ristea,Alexandru Jipa,Tiberiu Esanu,Vanea Covlea,Catalin Ristea,Marius Calin,Ionel Lazanu,Calin Besliu,S Lunardi,R Menegazzo,C Bucci,A Nannini,C Signorini,P Di Nezza,M Chiari,J.J Valiente-Dobon,A Dainese,P.G Bizzeti

doi:10.1051/epjconf/20146604025

Abstract

In this work, we have analized the transverse momentum spectra of charged pions produced in Au+Au collisions at different energies using the non-extensive Tsallis distribution. The centrality and rapidity dependence of the non-extensivity parameter, q, is studied. In addition, comparisons with simulated heavy ion collisions data using the UrQMD code will be presented.

Highlights

High-energy heavy ion collisions provide an unique opportunity to study the nuclear matter under extreme conditions
Transverse momentum spectra of charged pions produced in Au+Au collisions at sNN = 200 GeV and measured by the BRAHMS experiment [5,6] were fitted using formula 1 and the fit parameter (q-1) is shown in Figure 1 as a function of the number of participants
The results suggest that the degree of non-equilibrium is higher in peripheral collisions

Summary

Introduction

High-energy heavy ion collisions provide an unique opportunity to study the nuclear matter under extreme conditions. The transverse momentum spectra can be described by this Tsallis distribution [4] characterized by a non-extensivity parameter q: hq pT It must be emphasized that in heavy ion collisions there could be other sources for temperature fluctuations, such as effects of resonance decays, kinetic non-equilibrium in the dynamics for the average trajectory in the phase-space.

Results

Conclusion