Statistical hadronization model for heavy-ion collisions in the few-GeV energy regime
S. Harabasz, Wojciech Florkowski, T. Galatyuk, Małgorzata Gumberidze, Radosław Ryblewski, P. Salabura, J. Stroth
Abstract
We show that the transverse-mass and rapidity spectra of protons and pions produced in Au-Au collisions at $\sqrt{{s}_{\mathrm{NN}}}\phantom{\rule{3.33333pt}{0ex}}=\phantom{\rule{3.33333pt}{0ex}}2.4$ GeV can be well reproduced in a thermodynamic model assuming single freeze-out of particles from a spherically symmetric hypersurface. This scenario corresponds to a physical picture used by Siemens and Rasmussen in the original formulation of the blast-wave model. Our framework modifies and extends this approach by incorporation of a Hubble-like expansion of QCD matter and inclusion of resonance decays. In particular, the $\mathrm{\ensuremath{\Delta}}(1232)$ resonance is taken into account, with a width obtained from the virial expansion. Altogether, our results bring evidence for substantial thermalization of the matter produced in heavy-ion collisions in the few-GeV energy regime and its nearly spherical expansion.