Search for the charged lepton flavour violating decay ${\eta }^{\prime }\to e\mu$

BESIII Collaboration, M. Ablikim, M. N. Achasov +765

Based on $(8998\pm 40)\times 10^6$ $J/\psi$ events collected in $e^{+}{e}^{-}$ collisions at $\sqrt{s}=3.097$ GeV with the BESIII detector, we present a search for the charged lepton flavou…