Spectra and femtoscopic scales in a hydrokinetic model for baryon-rich fireballs

Abstract

The hydrokinetic model and the scheme of dynamical freeze out proposed earlier for the RHIC energy are extended to lower colliding energy for non-vanishing baryon chemical potential. In this case a new two-phase equation of state is applied where baryon-rich hadronic matter is described within modified relativistic mean-field theory. As an example, the approach is employed for analyzing pion and kaon spectra and interferometry radii of Pb+Pb collisions at laboratory energies 40 and 158 AGeV. A good agreement is observed for the transverse mass dependence of the longitudinal radius for both energies studied. The transverse radii $R_{out}, R_{side}$ reproduce experiment at $E_{lab}=$158\ AGeV but at $E_{lab}=$40\ AGeV there is a marked (20 \%) difference from experimental points. This discrepancy is more noticeable in analysis of the ratio $R_{out}/R_{side}$. Nevertheless, considered examples of application of the hydrokinetic model with equation of state including the first order phase transition are quite successful and further development of the model is required.