Point-Coupling Models from Mesonic Hypermassive Limit and Mean-Field Approaches

TL;DR

This paper derives nonlinear point-coupling models from a meson-exchange framework using hypermassive meson limits and mean-field approaches, simplifying the interaction terms to fourth order in fermion condensates.

Contribution

It introduces two methods to derive point-coupling models from mesonic models, expanding the theoretical tools for nuclear matter modeling.

Findings

Derivation of point-coupling models via hypermassive meson limit.

Derivation of models using mean-field approximation.

Equations of state at zero temperature obtained for the models.

Abstract

In this work we show how nonlinear point-coupling models, described by a Lagrangian density that presents only terms up to fourth order in the fermion condensate $(\bar{\psi}\psi)$, are derived from a modified meson-exchange nonlinear Walecka model. The derivation can be done through two distinct methods, namely, the hypermassive meson limit within a functional integral approach, and the mean-field approximation in which equations of state at zero temperature of the nonlinear point-coupling models are directly obtained.