Speaker
Junya Sasaki
(Univ. of Tokyo)
Description
We evaluate the Michel parameters of $\tau$ decays using the full data sample of Belle. This is important to reveal the Lorentz structure of $\tau$ leptonic decays, which includes not only the $V - A$ interaction but also contributions from scalar, tensor and others that may arise from New Physics, thus testing lepton universality as well. We use both $\tau^+ \to l^+ \nu \bar{\nu}$ and $\tau^+ \to l^+ \gamma \nu \bar{\nu}$. We also measure branching fractions of $\tau$ decays into three charged leptons and two neutrinos. From this, we can constrain Michel-like parameters.
Primary author
Junya Sasaki
(Univ. of Tokyo)
