Radiative weak decays of baryons as single-quark transitions

Radiative weak decays are investigated in the context of the quark model assuming the basic transition is an $s$ quark decaying to a $d$ quark plus a photon. This assumption, which encompasses a number of more detailed models, is used to predict relative rates and angular distributions for radiative weak decays of baryons. The measured decay rate for ${\Sigma }^{+}\to p\gamma$ and upper limit on that for ${\Xi }^{-}\to {\Sigma }^{-}\gamma$ are in disagreement with the predictions and appear to rule out such models.