Search for the lepton-flavour violating decays $B^{+}\to K^{+}\hat{I}{¼}^{\pm }{e}^{\mp }$

Abstract

A search for the lepton-flavour violating decays $B^{+}\to K^{+}\hat{I}{¼}^{\pm }{e}^{\mp }$ is performed using a sample of proton-proton collision data, collected with the LHCb experiment at centre-of-mass energies of $7$ and $8\mathrm{TeV}$ and corresponding to an integrated luminosity of 3$\mathrm{f}{\mathrm{b}}^{-1}$. No significant signal is observed, and upper limits on the branching fractions are set as $\mathcal{B}(B^{+}\to K^{+}\hat{I}{¼}^{-}{e}^{+})<7.0(9.5)\times 10^{-9}$ and $\mathcal{B}(B^{+}\to K^{+}\hat{I}{¼}^{+}{e}^{-})<6.4(8.8)\times 10^{-9}$ at 90 (95) % confidence level. The results improve the current best limits on these decays by more than one order of magnitude.

All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2019-022.html