Frequency of the decay mode Σ+→p+γ

Abstract

We have searched for events which could be attributed to the rare mode of decay Σ+→p+γ. These events in nuclear emulsion will give a proton of unique range 3045 µm. We have found four events consistent with this interpretation in a sample which contained 264 normal decays Σ+→p+π0. Taking into account background which could come from Σ− one-prong stars or decays in flight of very slow Σ+ in the normal way, we estimate the frequency of Σ+→p+γ to be about 1% that of Σ+→p+π0.