A QCD Sum Rule Approach to the $s\to dγ$ Contribution to the $Ω^-\to Ξ^-γ$ Radiative Decay

Abstract

QCD sum rules are used to calculate the contribution of short-distance single-quark transition $s\rightarrow d γ$, to the amplitudes of the hyperon radiative decay, $Ω^-\rightarrow Ξ^-γ$. 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.