Measurement of the branching fraction of $B^+ \to \tau^+ \nu_\tau$   decays with the semileptonic tagging method and the full Belle data sample
  We report a measurement of the branching fraction of $B^+ \to \tau^+ \nu_\tau$ decays using a data sample of $772 \times 10^6 B \bar{B}$ pairs, collected at the $\Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. We reconstruct the accompanying $B$ meson in a semileptonic decay and detect the $B^+ \to \tau^+ \nu_\tau$ candidate in the recoiling event. We obtain a branching fraction of ${\cal B}(B^+ \to \tau^+ \nu_\tau) = [1.25 \pm 0.28 ({\rm stat.}) \pm 0.27({\rm syst.})] \times 10^{-4}$. This result is in good agreement with previous measurements and the expectation from calculations based on the Standard Model. 
Belle Collaboration: A. Abdesselam, I. Adachi, K. Adamczyk, H. Aihara,   S. Al Said, K. Arinstein, Y. Arita, D. M. Asner, T....
hep-ex