First measurement of the Ω− decay branching ratios

Abstract In an experiment in the CERN-SPS charged-hyperon beam, the main Ω − decay branching ratios have been measured to be Γ(Ω − →Λ K − /Γ( all )=0.686±0.013 , Γ(Ω −1 →Ξ 0 π − )/Γ( all )=0.234±0.013 , Γ(Ω − →Ξ − π 0 )/Γ( all )=0.080±0.008 . The relative branching ratio of the two Ξπ modes provides a test of the ΔI= 1 2 rule in decuplet-octet transitions. A search has also been made for the rare decay modes Ω − →Λπ − , Ω − →Ξ − γ, Ω − →Ξ − π + π − and Ω − →Ξ 0 e − ν .