SU(3) flavor symmetry breaking in large $N_c$ excited hyperons

TL;DR

This paper reviews the 1/N_c expansion method for excited baryons, focusing on hyperons and SU(3) symmetry breaking, successfully reproducing mass hierarchies and predicting unknown hyperon states.

Contribution

It provides a reanalysis of the [70, ℓ^+] multiplet with emphasis on hyperons and SU(3) breaking operators, offering new mass predictions for excited hyperons.

Findings

Mass hierarchy as a function of strangeness is correctly reproduced.

Predictions made for unknown excited hyperons in SU(6) × O(3) multiplets.

First-order SU(3) symmetry breaking operators effectively describe hyperon masses.

Abstract

The $1/N_c$ expansion method for studying the mass spectrum of excited baryons is shortly reviewed together with applications to mixed symmetric states. The $[{\bf 70, \ell^+}]$ multiplet, belonging to the $N$ = 2 band, is reanalyzed, with emphasis on hyperons and the SU(3) symmetry breaking operators entering the mass formula to first order. An important result is that the hierarchy of masses as a function of strangeness is correctly reproduced for all multiplets. Predictions for unknown excited hyperons to SU(6) $\times$ O(3) multiplets are made.