Pion couplings of the Delta(1232)

TL;DR

This paper calculates pion-Delta(1232) couplings using a QCD-based approach that includes multi-quark operators, revealing the importance of three-quark contributions for accurate results and their sensitivity to baryon structure.

Contribution

It introduces a comprehensive QCD parameterization including three-quark operators to accurately compute pion-baryon couplings, aligning with experimental data and advanced baryon models.

Findings

Three-quark operators are essential for accurate coupling calculations.

Results agree with models using large D state admixtures.

Pion-baryon couplings are sensitive to baryon spatial structure.

Abstract

We calculate the strong couplings of pions to the Delta(1232) resonance using a QCD parameterization method that includes in addition to the usual one-quark also two-quark and previously uncalculated three-quark operators. We find that three-quark operators are necessary to obtain results consistent with the data and other QCD based baryon structure models. Our results are also in quantitative agreement with a model employing large D state admixtures to the nucleon and Delta wave functions indicating that the pion-nucleon and pion-Delta couplings are sensitive to the spatial shape of these baryons.