On the possibility of P-violation at finite baryon-number densities

TL;DR

This paper explores how finite baryon density can induce spontaneous parity violation in hadronic matter using a sigma model approximation of QCD, revealing a novel mechanism involving meson interactions.

Contribution

It introduces a new mechanism for parity violation at finite baryon density based on meson interplay, distinct from previous pion-centric theories.

Findings

Finite baryon density can trigger spontaneous parity violation.

A novel meson interaction mechanism is proposed.

Relevance for dense nuclear matter at intermediate densities.

Abstract

We show how the introduction of a finite baryon density may trigger spontaneous parity violation in the hadronic phase of QCD. Since this involves strong interaction physics in an intermediate energy range we approximate QCD by a \sigma model that retains the two lowest scalar and pseudoscalar multiplets. We propose a novel mechanism based on interplay between lightest and heavy meson states which cannot be realized solely in the Goldstone boson (pion) sector and thereby is unrelated to the one advocated by Migdal some time ago. Our approach is relevant for dense matter in an intermediate regime of few nuclear densities where quark percolation does not yet play a significant role.