Searches for charged-lepton-flavor violation in χbJ(1P) decays

We report the first searches for charged-lepton-flavor violation in decays of χbJ(1P) ($J=0, 1,$ and $2$) to a pair of charged leptons using 158 million $Υ(2S)$ 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 χbJ(1P) decays to e^±μ^∓ at the level of 10⁻⁶ and to e^±τ^∓ or μ^±τ^∓ at the level of 10⁻⁵. Limits on χb0(1P) decays are translated into bounds on the corresponding Wilson coefficients of scalar operators that mediate charged-lepton-flavor violation.