Chiral perturbation theory for vertical bar Delta I vertical bar=3/2 hyperon decays

We study the \Delta I\ = 3/2 amplitudes of hyperon non-leptonic decays of t he form B --> B-pi' in the context of chiral perturbation theory. The lowes t-order predictions are determined in terms of only one unknown parameter a nd are consistent within errors with current data. We investigate the theor etical uncertainty of these predictions by calculating the leading non-anal ytic corrections. We also present an estimate for the size of the S-wave La mbda and Xi decays which vanish at leading order. We find that the correcti ons to the lowest-order predictions are within the expectations of naive po wer counting and, therefore, that this picture can be tested more accuratel y with improved measurements. (C) 1999 Elsevier Science B.V. All rights res erved.