$|ΔI|=3/2$ non-leptonic hyperon decays in covariant baryon chiral perturbation theory

Abstract

Inspired by the recent BESIII measurements of non-leptonic hyperon decays, we reexamine their $|ΔI|=3/2$ amplitudes in covariant baryon chiral perturbation theory with the extended-on-mass-shell renormalization scheme. Using the same restricted set of diagrammatic topologies as in the early analyses in heavy baryon chiral perturbation theory, we assess the effects of relativistic corrections, explicit decuplet baryons, different spin-$3/2$ coupling schemes, and pion-loop contributions. Our results show that relativistic effects alone lead to only mild changes, while decuplet contributions, especially in the consistent-coupling scheme, significantly improve the fit quality. Pion-loop contributions further reduce the $χ^2$ values. We highlight the importance of the consistent coupling scheme in the decuplet sector for describing the selected $|ΔI|=3/2$ amplitudes.