Constraints on the in-medium nuclear interaction from chiral symmetry and lattice-QCD

In this paper we discuss the combined effects on nuclear matter properties of the quark confinement mechanism in nucleon and of the chiral effective potential resulting from the spontaneous breaking of the chiral symmetry in nuclear matter. One specific aim is to show that the replacement of a basic chiral potential (linear sigma model type) by the enriched Nambu–Jona-Lasinio (NJL) model potential is able to reproduce the saturation properties while strongly decreasing the tension with QCD properties. Based on this NJL prediction, it is shown that the chiral potential acquires a specific scalar field cubic dependence, which contributes to the three-body interaction. We also discuss the constraints induced by Lattice-QCD on the model parameters governing the saturation properties. We introduce the term “QCD-connected parameters” for these quantities. We demonstrate that chiral symmetry and Lattice-QCD provide coherent constraints on the in-medium nuclear interaction, suggesting a fundamental origin of the saturation mechanism.