TRANSITION TO DELTA-MATTER FROM HOT, DENSE NUCLEAR-MATTER WITHIN A RELATIVISTIC MEAN-FIELD FORMULATION OF THE NONLINEAR-SIGMA AND OMEGA-MODEL

An investigation of the transition to Delta matter is performed based on a relativistic mean field formulation of the nonlinear sigma and om ega model. We demonstrate that in addition to the Delta-meson coupling , the occurrence of the baryon resonance isomer also depends on the nu cleon-meson coupling. Our results show that for the favored phenomenol ogical value of m and K, the Delta isomer exists at baryon density si milar to 2-3 rho(0) if beta=1.31 is adopted. For universal coupling of the nucleon and Delta, the Delta density at baryon density similar to 2-3 rho(0) and temperature similar to 0.4-0.5 fm(-1) is about normal nuclear matter density, which is in accord with a recent experimental finding.