|Delta I|=3/2 Decays of Hyperons in Chiral Perturbation Theory (original) (raw)

We study the |∆I| = 3/2 amplitudes of the octet-hyperon decays B → B ′ π and of the decays Ω − → Ξπ in the context of heavy-baryon chiral perturbation theory. For the octet-hyperon decays, we investigate the theoretical uncertainty of the lowest-order predictions by calculating the leading nonanalytic corrections. We find that these corrections are within the expectations of naive power counting and, therefore, that this picture can be tested more accurately with improved measurements. For the Ω − decays, we obtain at leading order two operators responsible for the decays which also contribute at one loop to the octet-hyperon decays. These one-loop contributions are sufficiently large to suggest that the measured ratio Γ(Ω − → Ξ 0 π −)/Γ(Ω − → Ξ − π 0) ≈ 2.7 may be too large.