Transverse-momentum spectra and nuclear modification factor using Boltzmann Transport Equation with flow in Pb+Pb collisions at $\sqrt{s_{NN}} = 2.76$ TeV

Abstract.

In the continuation of our previous work, the transverse-momentum ($p_{T}$) spectra and nuclear modification factor ($R_{AA}$) are derived using the relaxation time approximation of Boltzmann Transport Equation (BTE). The initial $p_{T}$-distribution used to describe p + p collisions has been studied with the perturbative-Quantum Chromodynamics (pQCD) inspired power-law distribution, Hagedorn's empirical formula and with the Tsallis non-extensive statistical distribution. The non-extensive Tsallis distribution is observed to describe the complete range of the transverse-momentum spectra. The Boltzmann-Gibbs Blast Wave (BGBW) distribution is used as the equilibrium distribution in the present formalism, to describe the $p_{T}$-distribution and nuclear modification factor in nucleus-nucleus collisions. The experimental data for Pb+Pb collisions at $\sqrt{s_{NN}} = 2.76$ TeV at the Large Hadron Collider at CERN have been analyzed for pions, kaons, protons, $K^{\ast0}$ and $\phi$. It is observed that the present formalism while explaining the transverse-momentum spectra up to 5 GeV/c, explains the nuclear modification factor very well up to 8 GeV/c in $p_{T}$ for all these particles except for protons. $R_{AA}$ is found to be independent of the degree of non-extensivity, $q_{pp}$ after $p_{T} \sim 8$ GeV/c.