Search for lepton-flavor-violating tau-lepton decays to $ellgamma$ at Belle

Charged lepton flavor violation is forbidden in the Standard Model but possible in several new physics scenarios. In many of these models, the radiative decays $tau^{pm}rightarrowell^{pm}gamma$ ($ell=e,mu$) are predicted to have a sizeable probability, making them particularly interesting channels to search at various experiments. An updated search via $tau^{pm}rightarrowell^{pm}gamma$ using full data of the Belle experiment, corresponding to an integrated luminosity of 988 fb$^{-1}$, is reported for charged lepton flavor violation. No significant excess over background predictions from the Standard Model is observed, and the upper limits on the branching fractions, $mathcal{B}(tau^{pm}rightarrow mu^{pm}gamma)$ $leq$ $4.2times10^{-8}$ and $mathcal{B}(tau^{pm}rightarrow e^{pm}gamma)$ $leq$ $5.6times10^{-8}$, are set at 90% confidence level.