Renormalization of the baryon axial vector current in large-N_c chiral perturbation theory: Effects of the decuplet-octet mass difference and flavor symmetry breaking

TL;DR

This paper calculates the baryon axial vector current at one-loop in large-N_c chiral perturbation theory, including effects of the decuplet-octet mass difference and flavor symmetry breaking, and compares predictions with experimental data.

Contribution

It systematically incorporates decuplet-octet states and symmetry breaking effects into large-N_c chiral perturbation theory, providing improved predictions for baryon axial couplings.

Findings

Large-N_c cancellations observed in loop graphs

Theoretical predictions agree well with experimental data

Parameters of large-N_c baryon chiral perturbation theory are constrained

Abstract

The baryon axial vector current is computed at one-loop order in large-N_c baryon chiral perturbation theory, where N_c is the number of colors. Loop graphs with octet and decuplet intermediate states are systematically incorporated into the analysis and the effects of the decuplet-octet mass difference and SU(3) flavor symmetry breaking are accounted for. As expected, large-N_c cancellations between different one-loop graphs are observed as a consequence of the large-N_c spin-flavor symmetry of QCD baryons. Fitting our analytical formulas against experimental data on baryon semileptonic decays and the strong decays of decuplet baryons, a detailed numerical analysis regarding the determination of the basic parameters of large-N_c baryon chiral perturbation theory as well as the extraction of the baryon axial vector couplings is performed. The large-N_c baryon chiral perturbation theory predictions are in very good agreement both with the expectations from the 1/N_c expansion and with the experimental data.