At present, nothing is known experimentally about the slope of the dominant form factor in the decay $\Sigma \to \Lambda e^{+}{e}^{-}$. However, it is probably so small that radiative corrections to the decay are an essential complication. We calculate the soft-photon radiative corrections to the Dalitz plot and the spectrum in the mass of the electron-positron pair. The correction to the total decay rate involving hard photons is also evaluated.

• Received 6 July 1971

DOI:https://doi.org/10.1103/PhysRevD.4.3344