Analyses of pp, Cu-Cu, Au-Au and Pb-Pb Collisions by Tsallis-Pareto Type Function at RHIC and LHC Energies.

Abstract

The parameters revealing the collective behavior of hadronic matter extracted from the transverse momentum spectra of , , , , p, , , , , or , and or or produced in the most central and most peripheral gold–gold (–), copper–copper (–) and lead–lead (–) collisions at 62.4 GeV, 200 GeV and 2760 GeV, respectively, are reported. In addition to studying the nucleus–nucleus () collisions, we analyzed the particles mentioned above produced in collisions at the same center of mass energies (62.4 GeV, 200 GeV and 2760 GeV) to compare with the most peripheral collisions. We used the Tsallis–Pareto type function to extract the effective temperature from the transverse momentum spectra of the particles. The effective temperature is slightly larger in a central collision than in a peripheral collision and is mass-dependent. The mean transverse momentum and the multiplicity parameter () are extracted and have the same result as the effective temperature. All three extracted parameters in collisions are closer to the peripheral collisions at the same center of mass energy, revealing that the extracted parameters have the same thermodynamic nature. Furthermore, we report that the mean transverse momentum in the – collision is larger than that of the – and – collisions. At the same time, the latter two are nearly equal, which shows their comparatively strong dependence on energy and weak dependence on the size of the system. The multiplicity parameter, in central , depends on the interacting system’s size and is larger for the bigger system.