Electromagnetic structure of the low-lying baryons in covariant chiral perturbation theory

TL;DR

This paper calculates low-lying baryon magnetic moments using covariant chiral perturbation theory, improving previous models by including SU(3) breaking effects and predicting moments for decuplet baryons with good agreement to experimental data.

Contribution

The study advances baryon magnetic moment calculations by incorporating extended-on-mass-shell renormalization and SU(3) breaking effects, providing new predictions for decuplet baryons.

Findings

Improved description of octet baryon magnetic moments with SU(3) breaking effects.

Predicted magnetic moments for $\Delta(1232)$ multiplet agree with experimental data.

Successfully fixed unknown LEC using the $\Omega^-$ magnetic moment.

Abstract

We report a calculation of the low-lying baryon magnetic moments using covariant chiral perturbation theory within the extended-on-mass-shell renormalization scheme including intermediate octet and decuplet contributions. For the case of the baryon octet, we succeed to improve the Coleman-Glashow description by including the leading SU(3)$_F$-breaking effects coming from the lowest-order loops. We compare with previous attempts at the same order using heavy-baryon and covariant infrared chiral perturbation theory, and discuss the source of the differences. For the case of the decuplet-baryons we fix the only unknown LEC with the well measured magnetic dipole moment of the $\Omega^-$ and predict the corresponding ones of the $\Delta(1232)$ isospin multiplet. In particular we obtain $\mu_{\Delta^{++}}=6.0(6) \mu_N$ and $\mu_{\Delta^{+}}=2.84(34) \mu_N$ that compare well with the current experimental information.