Mass shift of sigma-Meson in Nuclear Matter

TL;DR

This paper investigates how the sigma meson’s mass changes in nuclear matter using the Walecka model, considering various couplings and mixing effects, and finds a decrease in mass with minor mixing contributions.

Contribution

It introduces a comprehensive analysis of sigma meson mass shift in nuclear matter, including sigma-omega mixing and pion couplings, within the Walecka model framework.

Findings

Sigma meson mass decreases in nuclear matter

Sigma-omega mixing has a small effect on mass shift

Coupling to virtual pions is included in the analysis

Abstract

The propagation of sigma meson in nuclear matter is studied in the Walecka model, assuming that the sigma couples to a pair of nucleon-antinucleon states and to particle-hole states, including the in medium effect of sigma-omega mixing. We have also considered, by completeness, the coupling of sigma to two virtual pions. We have found that the sigma meson mass decreases respect to its value in vacuum and that the contribution of the sigma omega mixing effect on the mass shift is relatively small.