Search for B⁰ → τ^± ℓ^∓ (ℓ=e,μ) with a hadronic tagging method at Belle

2021/08/26 by Belle Collaboration, Atmacan, H., Schwartz, A. J. +219
#FOS: Physical sciences #High Energy Physics - Experiment (hep-ex)

paper · doi:10.48550/arxiv.2108.11649

Abstract

We present a search for the lepton-flavor-violating decays B⁰ → τ^± ℓ^∓, where ℓ=(e, μ), using the full data sample of 772 × 10⁶ B B pairs recorded by the Belle detector at the KEKB asymmetric-energy e⁺e^- collider. We use events in which one B meson is fully reconstructed in a hadronic decay mode. The τ^± lepton is reconstructed indirectly using the momentum of the reconstructed B and that of the ℓ^∓ from the signal decay. We find no evidence for B⁰ → τ^± ℓ^∓ decays and set upper limits on their branching fractions at 90% confidence level of \cal B(B⁰ → τ^± μ^∓) < 1.5 × 10^-5 and \cal B(B⁰ → τ^± e^∓) < 1.6 × 10^-5.

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