Spectra of Protons and Subthreshold Pions for Collisions of Heavy Ions Using a Hydrodynamic Approach with a Nonequilibrium Equation of State

Abstract

The nonequilibrium equation of state is studied in the context of the hydrodynamic approach. The compression stage, the expansion stage, and the freeze-out stage of the hot spot formed during the collisions of heavy ions are considered. The energy spectra of protons and subthreshold pions produced in collisions of heavy ions are calculated with inclusion of the nuclear viscosity effects and compared with experimental data for various combinations of colliding nuclei with energies of several tens of MeV per nucleon.