Searches for charged-lepton-flavor violation in ${\chi }_{bJ}(1P)$ decays

We report the first searches for charged-lepton-flavor violation in decays of ${\chi }_{bJ}(1P)$ ($J=0,1,$ and $2$) to a pair of charged leptons using 158 million $\mathrm{{\rm Y}}(2S)$ decays collected with the Belle detector in $e^{+}{e}^{-}$ collisions at the KEKB collider. No significant signal is observed, and we set upper limits on the branching fractions for ${\chi }_{bJ}(1P)$ decays to $e^{\pm }{\mu }^{\mp }$ at the level of ${10}^{-6}$ and to $e^{\pm }{\tau }^{\mp }$ or ${\mu }^{\pm }{\tau }^{\mp }$ at the level of ${10}^{-5}$. Limits on ${\chi }_{b0}(1P)$ decays are translated into bounds on the corresponding Wilson coefficients of scalar operators that mediate charged-lepton-flavor violation.