Search for charged lepton flavor violating decays of $Υ(1S)$
hep-ex
/ Authors
Belle Collaboration, S. Patra, V. Bhardwaj, K. Trabelsi, I. Adachi, H. Aihara, S. Al Said, D. M. Asner, H. Atmacan, T. Aushev
and 209 more authors
R. Ayad, V. Babu, S. Bahinipati, P. Behera, K. Belous, J. Bennett, M. Bessner, B. Bhuyan, T. Bilka, A. Bobrov, D. Bodrov, J. Borah, A. Bozek, M. Bračko, P. Branchini, T. E. Browder, A. Budano, M. Campajola, D. Červenkov, M. -C. Chang, P. Chang, A. Chen, B. G. Cheon, K. Chilikin
/ Abstract
We present a search for the charged lepton-flavor-violating decays $Υ(1S)\rightarrow\ell\ell^\prime$ and radiative charged lepton-flavour-violating decays $Υ(1S)\rightarrowγ\ell\ell^\prime$ [$\ell,\ell^\prime = e, μ, τ$] using the 158 million $Υ(2S)$ sample collected by the Belle detector at the KEKB collider. This search uses $Υ(1S)$ mesons produced in $π^+π^-Υ(1S)$ transitions. We do not find any significant signal, so we provide upper limits on the branching fractions at the 90% confidence level.