Scalar-Isovector Delta-Meson in the Relativistic Mean-Field Theory and the Structure of Neutron Stars with a Quark Core

TL;DR

This paper investigates how the scalar-isovector delta-meson influences the equation of state of superdense nuclear matter and the structure of neutron stars with quark cores using relativistic mean-field theory and an improved MIT bag model.

Contribution

It introduces the delta-meson field into the relativistic mean-field framework and explores its effects on quark phase transition and neutron star stability with quark cores.

Findings

Delta-meson field affects the characteristics of the quark phase transition.

Models of neutron stars with quark cores are constructed for various bag parameters.

Energy release estimates for neutron star transformations are provided.

Abstract

In the framework of the relativistic mean-field theory, we have considered the equation of state of superdense nuclear matter, taking into account an effective scalar-isovector delta-meson field. The effect of the delta-meson field on the characteristics of a Maxwell-type quark phase transition has been studied. The quark phase is described with the aid of the improved version of the MIT (Massachusetts Institute of Technology) bag model, in which interactions between the u, d, s quarks inside the bag are taken into account in the one-gluon exchange approximation. For different values of the bag parameter B, series of neutron star models with a quark core have been built. Stability problems for neutron stars with an infinitesimal quark core are discussed. An estimate is obtained for the amount of energy released in a catastrophic transformation of a critical neutron star to a star with a finite-size quark core.