Decoupling of non-strange, strange and multi-strange particles from the system in Cu–Cu, Au–Au and Pb–Pb collisions at high energies

Abstract

Transverse momentum spectra of the non-strange, strange and multi-strange particles in central and peripheral Copper–Copper, Gold–Gold and Lead–Lead collisions are analyzed by the blast wave model with Boltzmann Gibbs statistics. The model results are approximately in agreement with the experimental data measured by BRAHMS, STAR, SPS, NA 49 and WA 97 Collaborations in special transverse momentum ranges. Bulk properties in terms of kinetic freeze-out temperature, transverse flow velocity and freeze-out volume are extracted from the transverse momentum spectra of the particles. Separate freeze-out temperature is observed for the non-strange, strange and multi-strange particles which may be due to different reaction cross-section of the interacting particles and it reveals the triple kinetic freeze-out scenario in collisions at BRAHMS, STAR, SPS, NA 49 and WA 97 Collaborations. However the transverse flow velocity and kinetic freeze-out volume are mass-dependent, and both of them decrease for the massive particles. Furthermore, the kinetic freeze-out temperature, transverse flow velocity and kinetic freeze-out volume in central nucleus–nucleus collisions are larger than those in peripheral collisions. Besides, the larger kinetic freeze-out temperature and kinetic freeze-out volume are observed in the heaviest nuclei collisions, indicating their dependence on the size of interacting system.