Speaker
Description
We reconstruct the freeze-out state of the fireball produced in central Au+Au or Pb+Pb collisions in the energy range from 7.7 GeV up to 2760 GeV per colliding nucleon pair. The data stem from the RHIC beam energy scan programme and from the LHC. Transverse momentum spectra of protons, antiprotons, charged pions and kaons have been fitted. Blast-wave model is used. Resonance decays are fully taken into account and the fitting procedure uses Bayesian method with Gaussian process emulator. It is assumed that the fireball freezes-out chemically at chemical freeze-out temperature and then evolves in partial chemical equilibrium. We present how different resonance decays contribute to the spectrum at different energies. The freeze-out temperature decreases with increasing collision energy, while the transverse expansion velocity grows. The decrease of the freeze-out temperature seems to stop at the collision energy of 130 GeV; afterwards the temperature stays constant or grows slightly.
