Search for the lepton flavour violating decay $B^{+}\to K^{+}\hat{I}{¼}^{-}\ddot{I}{„}^{+}$ using $B_{s2}^{\ast 0}$ decays

Abstract

A search is presented for the lepton flavour violating decay $B^{+}\to K^{+}\hat{I}{¼}^{-}\ddot{I}{„}^{+}$ 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 $\ddot{I}„$ leptons are selected inclusively, primarily via decays with a single charged particle. The four-momentum of the $\ddot{I}„$ lepton is determined by using $B^{+}$ mesons from $B_{s2}^{\ast 0}\to B^{+}{K}^{-}$ decays. No significant excess is observed, and an upper limit is set on the branching fraction $B(B^{+}\to K^{+}\hat{I}{¼}^{-}\ddot{I}{„}^{+})<3.9\times 10^{-5}$ at 90% confidence level. The obtained limit is comparable to the world-best limit.

All figures and tables, along with machine-readable versions and any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2019-043.html (LHCb public pages)