On the leptonic decays of the $\tau$

Martin Hoferichter, Alberto Lusiani, Yannick Ulrich

In view of potential future improvements in the branching fractions of leptonic $\tau$ decays $\tau \to \ell {\nu }_{\tau }{\bar{\nu }}_{\ell }$, $\ell =e,\mu$, it is timely to derive the corresponding Standard-Mo…