Search for lepton-flavor-violating tau-lepton decays to $\ell\gamma$ at Belle
Abstract
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 $\tau^{\pm}\rightarrow\ell^{\pm}\gamma$ ($\ell=e,\mu$) are predicted to have a sizeable probability, making them particularly interesting channels to search at various experiments. An updated search via $\tau^{\pm}\rightarrow\ell^{\pm}\gamma$ 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, $\mathcal{B}(\tau^{\pm}\rightarrow \mu^{\pm}\gamma)$ $\leq$ $4.2\times10^{-8}$ and $\mathcal{B}(\tau^{\pm}\rightarrow e^{\pm}\gamma)$ $\leq$ $5.6\times10^{-8}$, are set at 90\% confidence level.
- Publication:
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arXiv e-prints
- Pub Date:
- March 2021
- DOI:
- 10.48550/arXiv.2103.12994
- arXiv:
- arXiv:2103.12994
- Bibcode:
- 2021arXiv210312994U
- Keywords:
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- High Energy Physics - Experiment
- E-Print:
- doi:10.1007/JHEP10(2021)019