Mapping chiral symmetry breaking in the excited baryon spectrum

TL;DR

This paper investigates how chiral symmetry breaking affects the spectrum of highly excited light baryons using a QCD-based model, revealing complex patterns of chiral symmetry restoration at high energies.

Contribution

It provides a detailed theoretical computation of the excited baryon spectrum considering chiral symmetry, using a variational approach within a Coulomb gauge QCD framework.

Findings

Chiral symmetry shows signs of restoration at high excitation energies.

The baryon spectrum exhibits more complex chiral symmetry patterns than previously thought.

The study covers baryons with spins up to 13/2 and includes multiple isospin states.

Abstract

We study the conjectured "Insensitivity to Chiral Symmetry Breaking" in the highly excited light baryon spectrum. While the experimental spectrum is being measured at JLab and CBELSA/TAPS, this insensitivity remains to be computed theoretically in detail. As the only existing option to have both confinement, highly excited states and chiral symmetry, we adopt the truncated Coulomb gauge formulation of QCD, considering a linearly confining Coulomb term. Adopting a systematic and numerically intensive variational treatment up to 12 harmonic oscillator shells we are able to access several angular and radial excitations. We compute both the excited spectra of $I=1/2$ and $I=3/2$ baryons, up to large spin $J=13/2$, and study in detail the proposed chiral multiplets. While the static-light and light-light spectra clearly show chiral symmetry restoration high in the spectrum, the realization of chiral symmetry is more complicated in the baryon spectrum than earlier expected.