First evidence of the decay B⁺→π⁺ e⁺ e^-

2026/04/29 by LHCb collaboration, R. Aaij, A. S. W. Abdelmotteleb +1182 · 2 voices
#hep-ex

paper · pdf

Abstract

The first evidence for the decay B⁺→π⁺ 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 3.2σ is observed and the branching fraction is measured to be \calBR(B⁺→π⁺ e⁺ e^-) = (2.4 ^+0.9_-0.8 ^+0.4_-0.2) × 10^-8, where the first set of uncertainties is statistical and the second is systematic. The result is consistent with the Standard Model expectation.

Citations

• Measurement of the branching fraction ratio R_K at large dilepton invariant mass
• Presentation of search results: theCLstechnique
• The Large-Sample Distribution of the Likelihood Ratio for Testing Composite Hypotheses

Discussions

• First evidence of the decay B⁺→K⁺e⁺e⁻ - A signal excess with a significance of 3.2σ is observed and the branching fraction is measured to be BR(B⁺→K⁺e⁺e⁻)=(2.4+0.9−0.8+0.4−0.2)×10⁻⁸, where the first s [bsky, 6 points, 0 comments]
• #LHCbpaper: First evidence of the decay B⁺ → π⁺ e⁺ e⁻ (arXiv:2604.26784) https://arxiv.org/abs/2604.26784 [bsky, 1 points, 0 comments]

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• Search for the lepton-flavour violating decays B⁺ → π⁺ μ^± e^∓
• First observation of the charmless baryonic decay B⁺→Λppp