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

Adachi, I.; Adamczyk, K.; Ahmed, H.; Ahn, Y.; Aihara, H.; Akopov, N.; Alhakami, M.; Aloisio, A.; Althubiti, N.; Angelsmark, M.

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

Belle-II

Collaboration

Feb 7, 2025

16 pages

e-Print:

2502.04885 [hep-ex]

Report number:

Belle II preprint 2024-033,
KEK preprint 2024-48

Experiments:

KEK-BF-BELLE-II

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Abstract: (arXiv)

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}

.

References(38)

Figures(0)

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Measurement of B+→τ+ντB^+\to\tau^+\nu_\tauB+→τ+ντ​ branching fraction with a hadronic tagging method at Belle II

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