Chiral symmetry, Confinement and Nuclear Matter properties

TL;DR

This paper explores how fundamental QCD properties like chiral symmetry breaking and nucleon substructure influence nuclear matter, proposing a chiral relativistic model that aligns with lattice results and describes bulk properties effectively.

Contribution

It introduces a chiral version of the relativistic $\sigma-\omega$ model incorporating nucleon substructure and lattice-based parameters, improving the understanding of nuclear matter properties.

Findings

Successful description of bulk nuclear matter properties.

Inclusion of pion loops and rho meson exchange improves model accuracy.

Parameter estimation from lattice QCD results enhances model reliability.

Abstract

We discuss the possible influence of fundamental QCD properties such as spontaneous chiral symmetry breaking and nucleon substructure on nuclear matter properties. We propose a chiral version of the relativistic $\sigma-\omega$ model in which the attractive background scalar field is associated with the chiral invariant field governing the radial fluctuations of the quark condensate. Nuclear matter stability is ensured once the scalar response of the nucleon depending on the quark confinement mechanism is properly incorporated. The needed parameters are estimated from lattice results and a satisfactory description of bulk properties follows, the only really free parameter being the $\omega NN$ coupling constant. Pion loops can be also incorporated to obtain in a consistent way the finite density chiral susceptibilities. A good description of the asymmetry energy is obtained once the full rho meson exchange and Fock terms are included.