Phase structure in a chiral model of nuclear matter

Abstract

The phase structure of symmetric nuclear matter in the extended Nambu-Jona-Lasinio (ENJL) model is studied by means of the effective potential in the one-loop approximation. It is found that chiral symmetry gets restored at high nuclear density and a typical first-order phase transition of the liquid-gas transition occurs at zero temperature, $T=0$, which weakens as $T$ grows and eventually ends up with a second-order critical point at $T=20$ MeV. This phase transition scenario is confirmed by investigating the evolution of the effective potential versus the effective nucleon mass and the equation of state.