QCD susceptibilities and nuclear matter saturation in a chiral theory: Inclusion of pion loops

Abstract

We derive the equation of state of symmetric nuclear matter in a relativistic theory with \ensuremath{\sigma} and \ensuremath{\omega} exchange. We take a chiral version of this model which insures all the chiral constraints. Going beyond the mean field approach we introduce the effects of the pion loops. For the parameters of the model, in order to fix those linked to pion exchange, we exploit the most recent information on the short-range part of the spin-isospin interaction. For those linked to the scalar meson exchange we make use of an analysis of lattice results on the nucleon mass evolution with the quark mass. With these inputs we are able reach a correct description of the saturation properties. From the equation of state of symmetric nuclear matter we also derive the density dependence of the quark condensate and of the QCD susceptibilities.