Measurement of $B^+\to\tau^+\nu_\tau$ branching fraction with a hadronic tagging method at Belle II

Sumitted to PubDB: 2024-11-04

Category: Physics / performance paper, Visibility: Latest Version Public

Authors	Michele Aversano, Guglielmo De Nardo, Giovanni Gaudino, Toru Iijima, Mario Merola
Date	2025-10-14
Working group	Semileptonic and Missing Energy Decay
Belle II Number	BELLE2-PUB-DRAFT-2024-013
Abstract	We present a measurement of the branching fraction of $B^+\to\tau^+\nu_\tau$ decays using $(387\pm6)\times 10^6$ $\Upsilon(4S)$ 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 $\mathcal{B}(B^+\to\tau^+\nu_\tau) = [1.24 \pm 0.41 (\text{stat.}) \pm 0.19 (\text{syst.})] \times 10^{-4}$.
ArXiv	https://arxiv.org/abs/2502.04885
Inspire	https://inspirehep.net/literature/2877701
Journal	Phys.Rev.D
Authorship confirmation page	https://authors.belle2.org/#75
Analysis	Measurement of $B^{+}\rightarrow \tau^{+}\nu_{\tau}$ branching ratio with a hadronic tagging method at Belle II