Analyzing Transverse Momentum Spectra of Pions, Kaons and Protons in p-p, p-A and A-A Collisions via the Blast-Wave Model with Fluctuations.

The transverse momentum spectra of different types of particles, π±, K±, p and p¯, produced at mid-(pseudo)rapidity in different centrality lead-lead (Pb-Pb) collisions at 2.76 TeV; proton-lead (p-Pb) collisions at 5.02 TeV; xenon-xenon (Xe-Xe) collisions at 5.44 TeV; and proton-proton (p-p) collisions at 0.9, 2.76, 5.02, 7 and 13 TeV, were analyzed by the blast-wave model with fluctuations. With the experimental data measured by the ALICE and CMS Collaborations at the Large Hadron Collider (LHC), the kinetic freeze-out temperature, transverse flow velocity and proper time were extracted from fitting the transverse momentum spectra. In nucleus-nucleus (A-A) and proton-nucleus (p-A) collisions, the three parameters decrease with the decrease of event centrality from central to peripheral, indicating higher degrees of excitation, quicker expansion velocities and longer evolution times for central collisions. In p-p collisions, the kinetic freeze-out temperature is nearly invariant with the increase of energy, though the transverse flow velocity and proper time increase slightly, in the considered energy range.