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Bibliographic Details
Main Author: Gaudino, Giovanni
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2506.03000
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Table of Contents:
  • We presented at Moriond EW 2025 a measurement of the branching fraction of $B\toτν$ decays using $(387\pm 6) \times 10^6$ $Υ(4S)$ collected between 2019 and 2022 with the Belle~II detector at the SuperKEKB $e^+e^-$ collider. We reconstruct the accompanying $B^-$ meson using the hadronic tagging method, while $B\toτν$ candidates are identified in the recoil. We find evidence for $B\toτν$ decays at 3.0 standard deviations, including systematic uncertainties. The measured branching fraction is $\mathcal{B}(B\rightarrowτν) = [1.24 \pm 0.41~\text{(stat.)} \pm 0.19~\text{(syst.)}] \times 10^{-4}$