Search for the lepton flavour violating decay B+→K+μ−τ+ using B∗0s2 decays
A search is presented for the lepton flavour violating decay B+→K+μ−τ+using a sample of proton--proton collisions at centre-of-mass energies of 7, 8, and 13 TeV, collected with the LHCb detector and corresponding to a total integrated luminosity of 9 fb−1. The τ leptons are selected inclusively, primarily via decays with a single charged particle. The four-momentum of the τ lepton is determined by using B+ mesons from B∗0s2→B+K− decays. No significant excess is observed, and an upper limit is set on the branching fraction B(B+→K+μ−τ+)<3.9×10−5 at 90 confidence level. The obtained limit is comparable to the world-best limit.