SU(6) $[{\bf 70},1^-]$ baryon multiplet in the $1/N_c$ expansion

TL;DR

This paper calculates the masses of excited baryon states within the SU(6) symmetry framework using the 1/Nc expansion, introducing a new method to simplify the operator analysis and emphasizing the importance of flavor and spin operators.

Contribution

It extends previous SU(4) studies to SU(6), providing a new method that reduces the number of operators in the mass formula and clarifies the role of flavor operators in baryon mass calculations.

Findings

Flavor and spin operators both contribute significantly to flavor-spin breaking.

The new method reduces the number of independent operators needed.

Results reinforce the importance of flavor operators in baryon mass models.

Abstract

The masses of excited states of mixed orbital symmetry of nonstrange and strange baryons belonging to the lowest $[{\bf 70},1^-]$ multiplet are calculated in the $1/N_c$ expansion to order $1/N_c$ with a new method which allows to considerably reduce the number of linearly independent operators entering the mass formula. This study represents an extension to SU(6) of our work on nonstrange baryons, the framework of which was SU(4). The conclusion regarding the role of the flavor operator, neglected in previous SU(6) studies, is reinforced. Namely, both the flavor and spin operators contribute dominantly to the flavor-spin breaking.