Narrow Results

The experimental invariant transverse momentum $(p_t)$ spectra of the charged pions and kaons, protons and antiprotons, produced at midrapidity in central (0–10%) Au$+$Au collisions at ${(s_{nn})}^{1/2}=62.4\mathrm{\text{GeV}}$, central (0–10%) Cu$+$Cu collisions at ${(s_{nn})}^{1/2}=200\mathrm{\text{GeV}}$, central (0–10%) Au$+$Au collisions at ${(s_{nn})}^{1/2}=200\mathrm{\text{GeV}}$, and central (0–5%) Pb$+$Pb collisions at ${(s_{nn})}^{1/2}=2.76\mathrm{\text{TeV}}$, 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 ${\chi }^2$ fits of the experimental invariant $p_t$ 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 $p_t$ in each studied collision system, and the values of the average transverse expansion velocity $(〈{\beta }_t〉)$ and global kinetic freeze-out temperature $(T_{fo})$ and their dependencies on the collision system $(〈N_{\mathrm{\text{part}}}〉)$ and ${(s_{nn})}^{1/2}$ were extracted. The combined (simultaneous) fits using Hagedorn formula with the (embedded) simple transverse flow describe well the experimental invariant $p_t$ spectra of the charged pions, kaons, protons and antiprotons in the whole measured range in region $p_t\ge 0.5\mathrm{\text{GeV}}/c$ in the analyzed central heavy ion collisions at RHIC and LHC, reproducing qualitatively well all the established dependencies of the parameters $〈{\beta }_t〉$ and $T_{fo}$ on the collision system $(〈N_{\mathrm{\text{part}}}〉)$ and ${(s_{nn})}^{1/2}$. The obtained results were compared with those of the previous analyses of high energy heavy ion collisions.