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 τ± → ℓ±γ (ℓ = e, μ) are predicted to have a sizeable probability, making them particularly interesting channels to search at various experiments. An updated search via τ± → ℓ±γ 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, \( \mathcal{B} \)(τ± → μ±γ) ≤ 4.2 × 10−8 and \( \mathcal{B} \)(τ± → e±γ) ≤ 5.6 × 10−8, are set at 90% confidence level.

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The BELLE collaboration., Uno, K., Hayasaka, K. et al. Search for lepton-flavor-violating tau-lepton decays to ℓγ at Belle. J. High Energ. Phys. 2021, 19 (2021). https://doi.org/10.1007/JHEP10(2021)019
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DOI: https://doi.org/10.1007/JHEP10(2021)019