Speaker
Description
The midrapidity transverse momentum (pt) distributions of the charged pions and kaons, protons and antiprotons, measured by ALICE Collaboration at nine centrality groups of Xe+Xe collisions at (snn)1/2=5.44 TeV, have been described quite well using simultaneous (combined) minimum χ2 fits with the simple (non-consistent) as well as thermodynamically consistent Tsallis function with included transverse flow. The parameters T0, 〈β_t 〉, and q extracted in Xe+Xe collisions at (snn)1/2=5.44 TeV using both consistent and non-consistent Tsallis function with included transverse flow have demonstrated the similar dependencies on collision centrality (<Npart>). The obtained non-extensivity parameter q values decrease systematically for all studied particle species with increasing Xe+Xe collision centrality, suggesting an increase in degree of system thermalization with increasing centrality of heavy-ion collisions. The extracted average transverse flow velocity has demonstrated significantly different growth rates in regions <Npart> < 44±5 and <Npart> > 44±5, and parameter T0 has stayed constant within uncertainties in <Npart> > 44±5 range in Xe+Xe collisions at (snn)1/2=5.44 TeV. It is argued that <Npart> 44±5 (<dNch/d> 158±20) could be a threshold border value for a crossover transition from a dense hadronic state to the QGP phase (or mixed phase of QGP and hadrons) in Xe+Xe collisions at (snn)1/2=5.44 TeV. The results obtained in present work for high-energy Xe+Xe collisions have been compared with those for high-energy Pb+Pb collisions at the LHC. Depletion (enhancement) of (p+p ̅)/(π^++π^-) ratio at low pt (intermediate pt) has been observed in present work in Xe+Xe collisions at (snn)1/2=5.44 TeV, which is consistent with the similar results of ALICE Collaboration obtained recently in high-energy Xe+Xe and Pb+Pb collisions at the LHC. Analyzing and reflecting the extracted 〈β_t 〉 versus <Npart> and (p+p ̅)/(π^++π^-) versus <dNch/d> dependencies, we have verified that the depletion (enhancement) of baryon-to-meson ratio at low pt (intermediate pt) values with increasing <dNch/d>, observed in high-energy Xe+Xe and Pb+Pb collisions at the LHC, is due to radial flow effects.
