Hardon-quark hybrid stars constructed by the nonlinear $\sigma$-$\omega$-$\rho$ mean-field model and MIT-bag model

TL;DR

This paper models hybrid stars composed of hadronic and strange quark matter using a nonlinear mean-field theory and MIT-bag model, revealing their increased stability at high densities compared to pure hadronic or quark stars.

Contribution

It introduces a self-consistent nonlinear $\sigma$-$\omega$-$\rho$ mean-field approach combined with the MIT-bag model to study hybrid star properties and stability.

Findings

Hybrid stars are more stable at high densities.

Different density-dependent behaviors of hyperons and quark matter.

Comparison of coupling constants from different models.

Abstract

Density-dependent relations among saturation properties of symmetric nuclear matter and hyperonic matter, properties of hadron-(strange) quark hybrid stars are discussed by applying the conserving nonlinear $\sigma$-$\omega$-$\rho$ hadronic mean-field theory. Nonlinear interactions that will be renormalized as effective coupling constants, effective masses and sources of equations of motion are constructed self-consistently by maintaining thermodynamic consistency to the mean-field approximation. The coupling constants expected from the hadronic mean-field model and SU(6) quark model for the vector coupling constants are compared; the coupling constants exhibit different density-dependent results for effective masses and binding energies of hyperons, properties of hadron and hadron-quark stars. The nonlinear $\sigma$-$\omega$-$\rho$ hadronic mean-field approximation with or without vacuum fluctuation corrections and strange quark matter defined by MIT-bag model are employed to examine properties of hadron-(strange) quark hybrid stars. We have found that hadron-(strange) quark hybrid stars become more stable in high density compared to pure hadronic and strange quark stars.