EOS at FAIR energies and the role of resonances

Two microscopic models, UrQMD and QGSM, are used to extract the effective equation of state (EOS) of locally equilibrated nuclear matter produced in heavy-ion collisions at energies from 11.6 A GeV to 160 A GeV. Analysis is performed for the fixed central cubic cell of volume V = 125 fm(3) and for the expanding cell that followed the growth of the central area with uniformly distributed energy. For all reactions the state of local equilibrium is nearly approached in both models after a certain relaxation period. The EOS has a simple linear dependence P = c(s)(2)epsilon with 0.12 <= c(s)(2) <= 0.145. Heavy resonances are shown to be responsible for deviations of the c(s)(2)(T) and c(s)(2) (mu(B)) from linear behavior. In the T-mu(B) and T-mu(S) planes the EOS has also almost linear dependence and demonstrates kinks related not to the deconfinement phase transition but to inelastic freeze-out in the system.