Leptonic and semileptonic decays with taus at the Belle II experiment

Abstract

Lepton flavour universality as predicted by the Standard Model is challenged by various measurements of meson decays involving tau and charged light leptons. The Belle II experiment started recording first collision data in spring 2018 and offers a unique laboratory to study lepton flavour universality in leptonic and semileptonic decays at high precision. Here we report the status of establishing first measurements of (semi) tauonic decays and preliminary results of the → gag channel using the available Belle II data, and discuss the future potential of investigating '( (∗) ) anomalies.