New results for rare muon decays

Branching-ratio limits obtained with the Crystal Box detector are presented for the rare muon decays ..mu.. ..-->.. eee, ..mu.. ..-->.. e..gamma.., and ..mu.. ..-->.. e..gamma gamma... These decays, which violate the conservation of separate lepton-family numbers, are expected to occur in many extensions to the standard model. We found no candidates for the decay ..mu.. ..-->.. eee, yielding an upper limit for the branching ratio of B/sub ..mu..3e/ .. e..gamma.. candidates yields an upper limit of B/sub ..mu..e..gamma../ .. e..gamma gamma.. candidates gives an upper limit of B/sub ..mu..e..gamma gamma../ < 7.2 x 10/sup -11/. These results strengthen the constraints on models that allow transitions between lepton families.