# The 16th International Workshop on Tau Lepton Physics (TAU2021) (Virtual Edition)

September 27, 2021 to October 1, 2021
Indiana University
America/Indiana/Indianapolis timezone

## Search for tau LFV/LNV decays at Belle

Sep 28, 2021, 8:25 AM
25m
Virtual (Indiana University)

### Virtual

#### Indiana University

Oral contribution

Kenta Uno

### Description

We report the result of a search for \tau \to \ell \gamma (\ell = e, \mu) using the full data sample at Belle. Charged lepton flavor violation (CLFV) is forbidden in the Standard Model but possible in several new physics scenarios.
In many of these models, the radiative decays $\tau \to \ell\gamma$ are predicted to have a sizeable probability and are thus particularly interesting CLFV channels. Consequently, we have obtained the most stringent limit on the branching fraction of \tau \to \mu \gamma. In addition, we report the result of a search for \tau \to p \ell \ell at Belle. Any observation of processes involving Lepton number and baryon number violation would be a clear signature of new physics. Consequently, we set the most stringent limits on the branching fraction of $\tau \to p \ell \ell$ .

### Presentation materials

 Tau2021_Kuno_28Sep21.pdf VideoTau2021_Uno.mp4