Indication of a Differential Freeze-Out in Proton-Proton and Heavy-Ion Collisions at RHIC and LHC Energies

Dhananjaya Thakur,Sushanta Tripathy,Prakhar Garg,Jean Cleymans,Raghunath Sahoo

doi:10.1155/2016/4149352

Dhananjaya Thakur, Sushanta Tripathy + Show 3 more

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https://doi.org/10.1155/2016/4149352

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Abstract

The experimental data from the RHIC and LHC experiments of invariant pT spectra for most peripheral A+A and p+p collisions are analyzed with Tsallis distributions in different approaches. The information about the freeze-out surface in terms of freeze-out volume, temperature, chemical potential, and radial flow velocity for π+, K+, and p and their antiparticles is obtained. Furthermore, these parameters are studied as a function of the mass of the particles. A mass dependent differential freeze-out is observed which does not seem to distinguish between particles and their antiparticles. Furthermore, a mass-hierarchy in the radial flow is observed, meaning heavier particles suffer lower radial flow. Tsallis distribution function at finite chemical potential is used to study the mass dependence of chemical potential. The peripheral heavy-ion and proton-proton collisions at the same energies seem to be equivalent in terms of the extracted thermodynamic parameters.

Highlights

High-energy heavy-ion collisions provide a unique opportunity to study the nuclear matter under extreme conditions, that is, at high temperature and/or density
We present a systematic study of the parameters extracted from transverse momentum spectra of produced identified particles in Au + Au collisions at √sNN = 200 GeV and Pb + Pb collisions at √sNN = 2.76 TeV
The chemical potential plays an important role in particle production mechanism

Summary

Introduction

High-energy heavy-ion collisions provide a unique opportunity to study the nuclear matter under extreme conditions, that is, at high temperature and/or density. The evolution of the partonic system created in highenergy experiments is generally believed to be best described by hydrodynamics of an almost ideal fluid [45] This approach gives a fair description of data on the transverse momentum spectra of hadrons, which are treated as one of the important tools to understand the production dynamics of particles in high-energy collisions. In case of peripheral collisions due to smaller number of participants the system will be away from equilibrium for a while as compared to central collisions Such a nonequilibrium system is better described by Tsallis nonextensive statistics, giving information about the various thermodynamic parameters of the system.

Nonextensivity and Transverse Momentum Spectra

Results and Discussion

Conclusion