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

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.

Comments: 15 pages, 7 figures.