Search for the rare leptonic decays B+→l+νl (l=e,μ)

Abstract

We have performed a search for the rare leptonic decays B + → ℓ + ν ℓ ( l = e , μ ), using data collected at the Υ ( 4 S ) resonance by the BABAR detector at the PEP-II storage ring. In a sample of 468 × 10 6 B ¯¯¯ B pairs we find no evidence for a signal and set an upper limit on the branching fractions B ( B + → μ + ν μ ) < 1.0 × 10 − 6 and B ( B + → e + ν e ) < 1.9 × 10 − 6 at the 90% confidence level, using a Bayesian approach.