Search for the exotic decay μ+→e+ν̄eνμ

Abstract We search for the exotic decay μ + →e + ν e ν μ as a test of lepton number conversation. An exposure of ≈10 20 μ + -decay neutrinos to a 15 ton detector leads to a new upper bound for the branching ratio, RϵΓ(μ + →e + ν e ν μ /Γ(μ + →all), R .