Chiral perturbation theory for \ΔI\ = 3/2 hyperon decays

We study the \ΔI\ = 3/2 amplitudes of hyperon non-leptonic decays of the form B → B′ π in the context of chiral perturbation theory. The lowest-order predictions are determined in terms of only one unknown parameter and are consistent within errors with current data. We investigate the theoretical uncertainty of these predictions by calculating the leading non-analytic corrections. We also present an estimate for the size of the S-wave Λ and Ξ decays which vanish at leading order. We find that the corrections to the lowest-order predictions are within the expectations of naive power counting and, therefore, that this picture can be tested more accurately with improved measurements.