Measurement of the branching ratio of $\bar{B} \to D^{(\ast)} \tau^- \bar{\nu}_\tau$ relative to $\bar{B} \to D^{(\ast)} \ell^- \bar{\nu}_\ell$ decays with hadronic tagging at Belle.

Abstract

We report a measurement of the branching fraction ratios of $\bar{B} \to D^{(\ast)} \tau^- \bar{\nu}_\tau$ relative to $\bar{B} \to D^{(\ast)} \ell^- \bar{\nu}_\ell$ decays with hadronic tagging using the full Belle data sample of 772 × 10^6 BBbar pairs collected at the Upsilon(4S0 resonance with the Belle detector at the KEKB asymmetric energy e+e- collider.