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

TL;DR

This paper reports the first evidence of the decay B+→π+ e+ e− using LHCb data, observing a 3.2σ excess and measuring its branching fraction consistent with the Standard Model.

Contribution

It provides the first experimental evidence for the rare decay B+→π+ e+ e− and measures its branching fraction using proton-proton collision data.

Findings

Observed a 3.2σ signal excess for B+→π+ e+ e− decay.

Measured branching fraction of (2.4^{+0.9}_{-0.8} ^{+0.4}_{-0.2})×10^{-8}.

Result aligns with Standard Model predictions.

Abstract

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 $\cal{BR}(B^+\to\pi^+ e^+ e^-) = (2.4\,{}^{+0.9}_{-0.8} \,{}^{+0.4}_{-0.2}) \times 10^{-8}$, where the first set of uncertainties is statistical and the second is systematic. The result is consistent with the Standard Model expectation.