Upper limit on the decay Σ(1385)−→Σ−γ and cross section for γΣ−→Λπ−

Abstract Coherent Λ π − production on Pb of 600 GeV Σ − hyperons has been studied with the SELEX facility at Fermilab. Using the Primakoff formalism, we set a 90% CL upper limit on the radiative decay width Γ [Σ(1385) − →Σ − γ ] γ Σ − →Λ π − at s ≈1.385  GeV to be 56±16 μb.