Chiral symmetry restoration with three chiral partners

TL;DR

This paper explores how chiral symmetry restoration at finite temperature affects the masses of chiral partners, including mesons with a double pole structure, proposing a new pattern of degeneracy at high temperatures.

Contribution

It introduces an effective theory for D mesons with a double pole structure and suggests a novel pattern of chiral symmetry restoration involving three mass degeneracies.

Findings

Degeneracy of mesons of opposite parity above the chiral transition temperature.

Introduction of a double pole structure for positive parity D mesons.

Proposed high-temperature restoration pattern with three mass degeneracies.

Abstract

I discuss the masses of chiral partners in the context of chiral symmetry restoration at finite temperature. Using the Nambu-Jona-Lasinio model I first remind the usual situation where two mesons of opposed parity become degenerate above the chiral transition temperature. Then I consider an effective theory for D mesons where the positive parity companion presents a "double pole structure". In this case three different masses need to be analyzed as functions of the temperature. I suggest a possible restoration pattern at high temperatures when the back-reaction of the quark condensate is incorporated.