Observation of ω → π0 μ+μ− decay

Abstract The results of studying the mass spectrum of μ + μ − γγ systems produced in π − p collisions at 25 and 33 GeV/c presented. The wide-aperture magnetic spectrometer with a hodoscope γ-detector was used to identify muon pairs and photons. There is a clear peak in the mass spectrum which corresponds to the decay ω → π 0 μ + μ − previously not observed. The branching ratio for the decay is estimated to be 9 × 10 −5 with a systematic error of 50%.