Orbitally Excited Baryons in Large N_c QCD

TL;DR

This paper analyzes the mass spectrum of nonstrange l=1 baryons using large N_c QCD, demonstrating the effectiveness of the 1/N_c expansion and connecting it to a constituent quark model with meson exchange.

Contribution

It provides a model-independent analysis of baryon masses in large N_c QCD, identifying key operators and supporting the 1/N_c expansion's validity.

Findings

Supports the validity of the 1/N_c expansion for baryon spectra

Identifies a few dominant operators in the effective basis

Connects results to a constituent quark model with meson exchange

Abstract

We present a model-independent analysis of the mass spectrum of nonstrange l=1 baryons in large N_c QCD. The 1/N_c expansion is used to select and order a basis of effective operators that spans the nine observables (seven masses and two mixing angles). Comparison to the data provides support for the validity of the 1/N_c expansion, but also reveals that only a few nontrivial operators are strongly preferred. We show that our results have a consistent interpretation in a constituent quark model with pseudoscalar meson exchange interactions.