$\bar{B}\to D\tau {\bar{\nu }}_{\tau }$ vs. $\bar{B}\to D\mu {\bar{\nu }}_{\mu }$

Damir Becirevic, Nejc Kosnik, Andrey Tayduganov

Recent experimental results for the ratio of the branching fractions of $\bar{B}\to D^{(\ast )}\tau {\bar{\nu }}_{\tau }$ and $\bar{B}\to D^{(\ast )}\mu {\bar{\nu }}_{\mu }$ decays came as a surprise and lead to a discus…