A test of lepton flavor universality with a measurement of $R(D^{\ast })$ using hadronic $B$ tagging at the Belle II experiment

Belle II Collaboration, I. Adachi, K. Adamczyk +434

The ratio of branching fractions $R(D^{\ast })=\mathcal{B}(\overline{B}\to D^{\ast }{\tau }^{-}{\overline{\nu }}_{\tau })$/$\mathcal{B} (\overline{B} \rightarrow D^{*} \ell^{-} \overlineν_{\ell}…