Search for the rare decay ({{{B} ^+}} !ightarrow {mu ^+} {mu ^-} {mu ^+} {{upnu } _mu } )

摘要

A search for the rare leptonic decay $${{{B} ^+}} !ightarrow {mu ^+} {mu ^-} {mu ^+} {{upnu } _mu } $$ B + → μ + μ - μ + ν μ is performed using proton-proton collision data corresponding to an integrated luminosity of $$4.7 , {hbox {fb}}^{-1}$$ 4.7 fb - 1 collected by the LHCb experiment. The search is carried out in the region where the lowest of the two $${mu ^+mu ^-} $$ μ + μ - mass combinations is below $$980 {mathrm {,MeV!/}c^2} $$ 980 MeV / c 2 . The data are consistent with the background-only hypothesis and an upper limit of $$1.6 imes 10^{-8}$$ 1.6 × 10 - 8 at 95% confidence level is set on the branching fraction in the stated kinematic region.