Search for charged-lepton flavor violation in $Υ(2S) \to \ell^\mpτ^\pm$ ($\ell=e,μ$) decays at Belle
hep-ex
/ Authors
R. Dhamija, S. Nishida, A. Giri, I. Adachi, H. Aihara, D. M. Asner, T. Aushev, R. Ayad, V. Babu, S. Bahinipati
and 171 more authors
Sw. Banerjee, M. Bauer, P. Behera, K. Belous, J. Bennett, M. Bessner, V. Bhardwaj, D. Biswas, D. Bodrov, J. Borah, A. Bozek, M. Bračko, P. Branchini, T. E. Browder, A. Budano, M. Campajola, D. Červenkov, M. -C. Chang, P. Chang, V. Chekelian, B. G. Cheon, K. Chilikin, H. E. Cho, K. Cho
/ Abstract
We report a search for the charged-lepton flavor violation in $Υ(2S) \to \ell^\mpτ^\pm$ ($\ell=e,μ$) decays using a $25~\fbi$ $Υ(2S)$ sample collected by the Belle detector at the KEKB $e^{+}$$e^-$ asymmetric-energy collider. We find no evidence for a signal and set upper limits on the branching fractions ($\mathcal{B}$) at 90\% confidence level. We obtain the most stringent upper limits: $\mathcal{B}(\Ytomutau) < 0.23 \times 10^{-6}$ and $\mathcal{B}(\Ytoetau) < 1.12 \times 10^{-6}$.