A QCD Sum Rule Approach to the $s\to d\gamma$ Contribution to the $\Omega^-\to \Xi^-\gamma$ Radiative Decay

Abstract

QCD sum rules are used to calculate the contribution of short-distance single-quark transition $s\rightarrow d \gamma$, to the amplitudes of the hyperon radiative decay, $\Omega^-\rightarrow \Xi^-\gamma$. We re-evaluate the Wilson coefficient of the effective operator responsible for this transition. We obtain a branching ratio which is comparable to the unitarity limit.