Measurement of $B^{+}\to {\tau }^{+}{\nu }_{\tau }$ branching fraction with a hadronic tagging method at Belle II

Abstract

We present a measurement of the branching fraction of $B^{+}\to {\tau }^{+}{\nu }_{\tau }$ decays using $(387\pm 6)\times 10^6$ ${\rm Y}(4S)$ 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 $B^{+}\to {\tau }^{+}{\nu }_{\tau }$ candidates are identified in the recoil. We find evidence for $B^{+}\to {\tau }^{+}{\nu }_{\tau }$ decays at 3.0 standard deviations, including systematic uncertainties. The measured branching fraction is $\mathcal{B}(B^{+}\to {\tau }^{+}{\nu }_{\tau })=[1.24\pm 0.41(\text{stat.})\pm 0.19(\text{syst.})]\times 10^{-4}$.

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• An Introduction to PYTHIA 8.2
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• The Design, Construction, Operation and Performance of the Belle II Silicon Vertex Detector
• Measurement of the integrated luminosity of data samples collected during 2019-2022 by the Belle II experiment
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Cited by in corpus (2)

• Study of $B^{+}\to {\mu }^{+}{\nu }_{\mu }$ decays at Belle and Belle II
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