Chiral-particle Approach to Hadrons in an Extended Chiral ($\sigma,\pi,\omega$) Mean-Field Model

TL;DR

This paper introduces an extended chiral mean-field model where hadron masses arise from chiral symmetry breaking, and compares its predictions with nonchiral models to understand the effects on nuclear matter and neutron stars.

Contribution

It presents a novel extended chiral ($\sigma,\pi,\omega$) mean-field model with mass generation via chiral symmetry breaking, differing from traditional models.

Findings

Chiral symmetry breaking significantly affects hadron masses and interaction coefficients.

The model impacts properties of nuclear and hyperonic matter, and neutron star characteristics.

Comparison shows notable differences from nonchiral mean-field models.

Abstract

The chiral nonlinear ($\sigma,\pi,\omega$) mean-field model is an extension of the conserving nonlinear (nonchiral) $\sigma$-$\omega$ hadronic mean-field model which is thermodynamically consistent, relativistic and Lorentz-covariant mean-field theory of hadrons. In the extended chiral ($\sigma,\pi,\omega$) mean-field model, all the masses of hadrons are produced by chiral symmetry breaking mechanism, which is different from other conventional chiral partner models. By comparing both nonchiral and chiral mean-field approximations, the effects of chiral symmetry breaking to the mass of $\sigma$-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.