Nuclear and neutron matter in the relativistic Brueckner-Hartree-Fock theory with next-to-leading order covariant chiral nuclear force

TL;DR

This paper applies the relativistic Brueckner-Hartree-Fock theory with next-to-leading order covariant chiral nuclear forces to investigate symmetric nuclear matter and pure neutron matter, achieving good agreement with empirical saturation properties.

Contribution

It introduces a fitting scheme for low-energy constants ensuring naturalness, and demonstrates improved predictions of nuclear matter properties at NLO compared to leading order.

Findings

Reproduces empirical saturation energy and density.

Shows softer equations of state at high densities.

Reduces dependence on momentum cutoff.

Abstract

The symmetric nuclear matter and pure neutron matter are investigated by the relativistic Brueckner-Hartree-Fock (RBHF) theory with the covariant chiral nuclear forces up to the next-to-leading order~(NLO). A fitting scheme to ensure the naturalness of the low-energy constants is proposed, which plays a crucial role in the proper description of nuclear matter. With a momentum cutoff $\Lambda=590$ MeV, the empirical saturation energy and density, as well as the incompressibility coefficient at the saturation density are reproduced well. The EoSs show less dependence on the momentum cutoff and become softer at densities above saturation density, in comparison with the previous leading order results. Given the good description for the saturation properties of nuclear matter, the present work encourages future studies of the finite nuclei in the framework of the RBHF theory with the NLO covariant chiral nuclear forces.