Kaons in Dense Half-Skyrmion Matter

TL;DR

This paper explores a novel phase of dense hadronic matter where chiral symmetry is restored but color confinement persists, predicting enhanced kaon attraction and implications for neutron stars.

Contribution

It introduces the concept of half-skyrmion and half-instanton matter phases and analyzes their effects on kaon properties in dense environments.

Findings

Enhanced attraction for anti-kaons in half-skyrmion matter.

Potential for kaon condensation in neutron-star matter.

Non-perturbative kaon behavior beyond chiral perturbation theory.

Abstract

Dense hadronic matter at low temperature is expected to be in crystal and at high density make a transition to a {\em chirally restored but color-confined} state which is a novel phase hitherto unexplored. This phase transition is predicted in both skyrmion matter in 4D and instanton matter in 5D, the former in the form of half-skyrmions and the latter in the form of half-instantons or dyons. We predict that when $K^-$'s are embedded in this half-skyrmion or half-instanton (dyonic) matter which may be reached not far above the normal density, there arises an enhanced attraction from the soft dilaton field figuring for the trace anomaly of QCD and the Wess-Zumino term. This attraction may have relevance for a possible strong binding of anti-kaons in dense nuclear matter and for kaon condensation in neutron-star matter. Such kaon property in the half-skyrmion phase is highly non-perturbarive and may not be accessible by low-order chiral perturbation theory. Relevance of the half-skyrmion or dyonic matter to compact stars is discussed.