Eur. Phys. J. A (2018) 54: 55
https://doi.org/10.1140/epja/i2018-12487-4

Regular Article - Theoretical Physics

p_T spectra in pp and AA collisions at RHIC and LHC energies using the Tsallis-Weibull approach

¹ Indian Institute of Technology Bombay, 400076, Mumbai, India
² Utkal University, Department of Physics, Vani Vihar, 751004, Bhubaneswar, Odisha, India

^* e-mail: sadhana@phy.iitb.ac.in

Received: 10 December 2017
Accepted: 20 February 2018
Published online: 16 April 2018

Abstract

The Tsallis q -statistics have been incorporated in the Weibull model of particle production, in the form of q-Weibull distribution, to describe the transverse momentum () distribution of charged hadrons at mid-rapidity, measured at RHIC and LHC energies. The q-Weibull distribution is found to describe the observed distributions over all ranges of measured . Below 2.2 GeV/c, while going from peripheral to central collisions, the parameter q is found to decrease systematically towards unity, indicating an evolution from a non-equilibrated system in peripheral collisions, towards a more thermalized system in central collisions. However, the trend is reversed in the all inclusive regime. This can be attributed to an increase in relative contribution of hard pQCD processes in central collisions. The -parameter is found to be associated with the mean or the collective expansion velocity of the produced hadrons, which shows an expected increase with centrality of collisions. The k parameter is observed to increase with the onset of hard QCD scatterings, initial fluctuations, and other processes leading to non-equilibrium conditions.