An evidence of mass-dependent differential kinetic freeze-out scenario observed in Pb-Pb collisions at 2.76 TeV

Hai-Ling Lao; Hua-Rong Wei; Fu-Hu Liu; Roy A. Lacey

doi:10.1140/epja/i2016-16203-2

EPJ

An evidence of mass-dependent differential kinetic freeze-out scenario observed in Pb-Pb collisions at 2.76 TeV

Hai-Ling Lao¹, Hua-Rong Wei¹, Fu-Hu Liu¹^* and Roy A. Lacey²

¹ Institute of Theoretical Physics, Shanxi University, 030006, Taiyuan, Shanxi, China
² Departments of Chemistry & Physics, Stony Brook University, 11794, Stony Brook, NY, USA

Received: 15 May 2016
Accepted: 7 July 2016
Published online: 26 July 2016

Abstract

Transverse momentum spectra of different particles produced in mid-rapidity interval in lead-lead (Pb-Pb) collisions with different centrality intervals, measured by the ALICE Collaboration at center-of-mass energy per nucleon pair $\sqrt{s_{NN}} = 2.76$ TeV, are conformably and approximately described by the Tsallis distribution. The dependences of parameters (effective temperature, entropy index, and normalization factor) on event centrality and particle rest mass are obtained. The source temperature at the kinetic freeze-out is obtained to be the intercept in the linear relation between effective temperature and particle rest mass, while the particle (transverse) flow velocity in the source rest frame is extracted to be the slope in the linear relation between mean (transverse) momentum and mean moving mass. It is shown that the source temperature increases with increase of particle rest mass, which exhibits an evidence of mass-dependent differential kinetic freeze-out scenario or multiple kinetic freeze-out scenario.

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EPJ

An evidence of mass-dependent differential kinetic freeze-out scenario observed in Pb-Pb collisions at 2.76 TeV

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