Measurement of the branching ratio of ${\bar{B}}^0\to D^{\ast +}{\tau }^{-}{\bar{\nu }}_{\tau }$ relative to ${\bar{B}}^0\to D^{\ast +}{\ell }^{-}{\bar{\nu }}_{\ell }$ decays with a semileptonic tagging method

A. Abdesselam, I. Adachi, K. Adamczyk +441

We report a measurement of ratio $\mathcal{R}(D^{\ast })=\mathcal{B}({\bar{B}}^0\to D^{\ast +}{\tau }^{-}{\bar{\nu }}_{\tau })/\mathcal{B}({\bar{B}}^0\to D^{\ast +}{\ell }^{-}{\bar{\nu }}_{\ell })$, where $\ell$ denot…