QCD sum rule approach to the s-->d gamma contribution to the Omega ---> Xi - gamma radiative decay.

Abstract

QCD sum rules are used to calculate the contribution of the short-distance single-quark transition s\ensuremath{\rightarrow}d\ensuremath{\gamma} to the amplitudes of the hyperon radiative decay ${\mathrm{\ensuremath{\Omega}}}^{\mathrm{\ensuremath{-}}}$\ensuremath{\rightarrow}${\mathrm{\ensuremath{\Xi}}}^{\mathrm{\ensuremath{-}}}$\ensuremath{\gamma}. We reevaluate the Wilson coefficient of the effective operator responsible for this transition. We obtain a branching ratio which is comparable to the unitarity limit. \textcopyright{} 1996 The American Physical Society.