Effective restoration of chiral symmetry in excited mesons

R.F Wagenbrunn,L.Ya Glozman

doi:10.1016/j.physletb.2006.10.044

Abstract

Abstract A fast restoration of chiral symmetry in excited mesons is demonstrated. A minimal “realistic” chirally symmetric confining model is used, where the only interaction between quarks is the linear instantaneous Lorentz-vector confining potential. Chiral symmetry breaking is generated via the nonperturbative resummation of valence quarks self-energy loops and the meson bound states are obtained from the Bethe–Salpeter equation. The excited mesons fall into approximate chiral multiplets and lie on the approximately linear radial and angular Regge trajectories, though a significant deviation from the linearity of the angular trajectory is observed.

Highlights

A fast restoration of chiral symmetry in excited mesons is demonstrated
There are certain phenomenological evidences that in highly excited hadrons, both in baryons [1, 2, 3] and mesons [4, 5] chiral and U(1)A symmetries are approximately restored, for a short overview see [6]. This ”effective” restoration of chiral and U(1)A symmetries should not be confused with the chiral symmetry restoration at high temperatures and/or densities
In principle any possible gluonic interaction can contribute to chiral symmetry breaking and it is not known which specific interaction is the most important one in this respect

Summary

Introduction

A fast restoration of chiral symmetry in excited mesons is demonstrated. A minimal ”realistic” chirally symmetric confining model is used, where the only interaction between quarks is the linear instantaneous Lorentz-vector confining potential. There are certain phenomenological evidences that in highly excited hadrons, both in baryons [1, 2, 3] and mesons [4, 5] chiral and U(1)A symmetries are approximately restored, for a short overview see [6]. The microscopical reason is that in high-lying hadrons a typical momentum of valence quarks is large and they decouple from the quark condensate and their Lorentz-scalar dynamical mass asymptotically vanishes [1, 3, 7, 10, 14].

Objectives

Results

Conclusion