Observation of the semileptonic decay B+→pp¯μ+νμ
The Cabibbo-suppressed semileptonic decay B+→pp⎯⎯⎯μ+νμ is observed for the first time using a sample of pp collisions corresponding to an integrated luminosity of 1.0, 2.0 and 1.7fb−1 at centre-of-mass energies of 7, 8 and 13TeV, respectively. The differential branching fraction is measured as a function of the pp⎯⎯⎯ invariant mass using the decay mode B+→J/ψK+ for normalisation. The total branching fraction is measured to be
where the first uncertainty is statistical, the second systematic and the third is from the uncertainty on the branching fraction of the normalisation channel.