First evidence of the decay $B^{+}\to {\pi }^{+}{e}^{+}{e}^{-}$

The first evidence for the decay $B^{+}\to {\pi }^{+}{e}^{+}{e}^{-}$ is reported using proton-proton collision data recorded by the LHCb experiment at centre-of-mass energies of 7, 8 and 13 TeV, corresponding to an integrated luminosity of 9 fb${}^{-1}$. A signal excess with a significance of 3.2$\sigma$ is observed and the branching fraction is measured to be $\mathcal{B}\mathcal{R}({\mathcal{B}}^{+}\to {\mathcal{\pi }}^{+}{\mathcal{e}}^{+}{\mathcal{e}}^{-})=(\mathcal{2.4}{}_{-\mathcal{0.8}}^{+\mathcal{0.9}}{}_{-\mathcal{0.2}}^{+\mathcal{0.4}})\times {\mathcal{10}}^{-\mathcal{8}}$, where the first set of uncertainties is statistical and the second is systematic. The result is consistent with the Standard Model expectation.