Inverse meson mass ordering in color-flavor-locking phase of high density QCD

TL;DR

This paper derives the effective Lagrangian for mesons in the CFL phase of high-density QCD, revealing an inverse meson mass ordering and providing detailed calculations of decay constants, velocities, and masses at large chemical potential.

Contribution

It introduces a detailed effective Lagrangian for mesons in the CFL phase and uncovers an inverse mass ordering, which is a novel insight into high-density QCD behavior.

Findings

Meson decay constants are linear in chemical potential mu.

Meson maximum velocities are close to the speed of sound.

Meson masses are significantly smaller and exhibit an inverse order compared to normal QCD.

Abstract

We derive the effective Lagrangian for the low-energy massive meson excitations of the color-flavor-locking (CFL) phase of QCD with 3 flavors of light quarks. We compute the decay constants, the maximum velocities, and the masses of the mesons at large baryon chemical potential mu. The decay constants are linear in mu. The meson maximum velocities are close to that of sound. The meson masses in the CFL phase are significantly smaller than in the normal QCD vacuum and depend only on bare quark masses. The order of the meson masses is, to some extent, reversed compared to that in the QCD vacuum. In particular, the lightest particle is eta'.