Meson Mass at Large Baryon Chemical Potential in Dense QCD

TL;DR

This paper analyzes meson masses in dense QCD with high baryon chemical potential, revealing their dependence on quark mass, gap, and chemical potential, and showing mesons become massless at infinite chemical potential.

Contribution

It derives a new expression for meson masses in dense QCD, considering invariants under chiral-axial symmetry, and clarifies their behavior at large chemical potential.

Findings

Meson mass squared scales as m_q^2 Δ Δ̄ / μ^2 ln(μ^2/Δ^2)

Mesons become massless as μ approaches infinity

Meson mass depends on three independent invariants under chiral-axial symmetry

Abstract

We reexamine the quark mass induced term in chiral Lagrangian in color-flavor locking phase in dense QCD, and show that the meson mass term is determined by three independent invariants under chiral-axial symmetry, and a meson mass is given in terms of the quark mass, gap, and the chemical potential by $m_{\pi}^2\sim m_q^2\Delta\bar{\Delta}/\mu^2\ln(\mu^2/\Delta^2)$. Thus mesons become massless as $\mu\to\infty$.