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.