Kinetic freeze-out in central heavy-ion collisions between 7.7 and 2760 GeV per nucleon pair

Abstract

We fit the single-particle pt spectra of identified pions, kaons, and (anti)protons from central collisions of gold or lead nuclei at energies between 7.7 and 2760 GeV per nucleon pair. The blast wave model with included resonance production and with an assumption of partial chemical equilibrium is used and the fits are performed with the help of a Gaussian emulator process. A kinetic freeze-out temperature is found about 100 MeV for the lowest collision energies and 80 MeV at the LHC. The average transverse expansion velocity grows with increasing from 0.45 to 0.65. Due to partial chemical equilibrium, the influence of resonance decays on the shape of the pt spectra for above 27 GeV is small.