Density-Dependent Properties of Hadronic Matter in an Extended Chiral (&em&σ&/em&, &em&π&/em&, &em&ω&/em&) Mean-Field Model

摘要

Density-dependent relations among saturation properties of symmetric nuclear matter and hyperonic matter, the coupling ratios (strengths) of hyperon matter, and properties of hadronic stars are discussed by applying the conserving chiral nonlinear ( s , p , w ) hadronic mean-field theory. The chiral nonlinear ( s , p , w ) mean-field theory is an extension of the conserving nonlinear (nonchiral) s - w hadronic mean-field theory which is thermodynamically consistent, relativistic and is a Lorentz-covariant mean-field theory of hadrons. The extended chiral ( s , p , w ) mean-field model is one of effective models of Quantum Hadrodynamics (QHD). All the masses of hadrons are produced by the spontaneous chiral symmetry breaking, which is different from other conventional chiral partner models. By comparing both nonchiral and chiral mean-field approximations, the effects of the chiral symmetry breaking mechanism on the mass of s -meson, coefficients of nonlinear interactions, coupling ratios of hyperons to nucleons and Fermi-liquid properties are investigated in nuclear matter, hyperonic matter, and neutron stars.