We have searched for the lepton-flavor-violating decay τ→eγ using a data sample of 86.7 fb -1 collected with the Belle detector at the KEKB asymmetric e + e - collider. No evidence for a signal is obtained, and we set an upper limit for the branching fraction B(τ→eγ)<3.9×10 -7 at the 90% C.L. © 2005 Elsevier B.V. All rights reserved.
Hayasaka, K., Abe, K., Abe, K., Aihara, H., Asano, Y., Aushev, T., … Žontar, D. (2005). Search for τ → eγ decay at Belle. Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 613(1–2), 20–28. https://doi.org/10.1016/j.physletb.2005.03.028