EOS OF NUCLEAR-MATTER AT FINITE-TEMPERATURE AND DENSITY IN THE 1 N EXPANSION OF THE RELATIVISTIC SIGMA-OMEGA MODEL/

The thermodynamic potential for nuclear matter is calculated in the 1/ N expansion of the relativistic sigma-omega model. The relativistic ex change and correlation parts, which are included in the next-to-leadin g-order terms, are calculated at finite temperature for all thermodyna mic observables. The thermodynamic consistency of the 1/N expansion is verified in the context of thermo field dynamics and the imaginary-ti me path-integral formalism. The equation of state (EOS) of nuclear mat ter at finite density and temperature is investigated and the various contributions to the thermodynamic observables are discussed. It is em phasized that the inclusion of the higher-order terms leads to a softe ning of the EOS, which is important in view of empirical information f rom heavy-ion collisions and astrophysics.