Average transverse expansion velocities and global freeze-out temperatures in central Cu + Cu, Au + Au, and Pb + Pb collisions at high energies at RHIC and LHC
Аннотация
The experimental invariant transverse momentum [Formula: see text] spectra of the charged pions and kaons, protons and antiprotons, produced at midrapidity in central (0–10%) Au[Formula: see text]Au collisions at [Formula: see text], central (0–10%) Cu[Formula: see text]Cu collisions at [Formula: see text], central (0–10%) Au[Formula: see text]Au collisions at [Formula: see text], and central (0–5%) Pb[Formula: see text]Pb collisions at [Formula: see text], measured by BRAHMS, STAR and ALICE collaborations, were analyzed using three different transverse expansion (blast-wave) models: Siemens–Rasmussen blast-wave model, Simple transverse flow model, and Simplified (hydro-inspired) blast-wave model of Schnedermann et al. Combined (simultaneous) minimum [Formula: see text] fits of the experimental invariant [Formula: see text] spectra of the charged pions and kaons, protons and antiprotons with the above three model functions were conducted, using the identical selected optimal fitting ranges in [Formula: see text] in each studied collision system, and the values of the average transverse expansion velocity [Formula: see text] and global kinetic freeze-out temperature [Formula: see text] and their dependencies on the collision system [Formula: see text] and [Formula: see text] were extracted. The combined (simultaneous) fits using Hagedorn formula with the (embedded) simple transverse flow describe well the experimental invariant [Formula: see text] spectra of the charged pions, kaons, protons and antiprotons in the whole measured range in region [Formula: see text] in the analyzed central heavy ion collisions at RHIC and LHC, reproducing qualitatively well all the established dependencies of the parameters [Formula: see text] and [Formula: see text] on the collision system [Formula: see text] and [Formula: see text]. The obtained results were compared with those of the previous analyses of high energy heavy ion collisions.