Effects of isospin imbalance on the chiral phase transition within a Chiral Dual Partner Model

Abstract

The chiral symmetry is a property of the fundamental theory of the strong interaction that is relevant for the hadronic physics. It is expected that at sufficiently high temperature and matter density, this symmetry becomes manifest. Within the Chiral Dual Partner Model the chiral transformation is implemented in such a way that a fermion mass term is allowed if the parity partner of each baryon is included in the framework. This model is used here to study possible manifestations of the chiral symmetry in dense nuclear matter, assuming constant isospin fraction. It is found that the onset of the odd parity baryons is associated with two branches of thermodynamical instabilities, one of them leads to a first order phase transition for temperatures below $T_c\simeq 11$ MeV. An analysis of these instabilities in the phase space is given, and neutron star matter is considered as a special case.