# Search for the lepton-flavor-violating decay ${B}^{0}\to {K}^{*0}{\mu }^{±}{e}^{\mp }$

09 October 2018

Abstract: We have searched for the lepton-flavor-violating decay ${B}^{0}\to {K}^{*0}{\mu }^{±}{e}^{\mp }$ using a data sample of $711\text{}\text{}{\mathrm{fb}}^{-1}$ that contains $772×{10}^{6}$ $B\overline{B}$ pairs. The data were collected near the $\Upsilon \left(4S\right)$ resonance with the Belle detector at the KEKB asymmetric-energy ${e}^{+}{e}^{-}$ collider. No signals were observed, and we set 90% confidence level upper limits on the branching fractions of $B\left({B}^{0}\to {K}^{*0}{\mu }^{+}{e}^{-}\right)<1.2×{10}^{-7}$, $B\left({B}^{0}\to {K}^{*0}{\mu }^{-}{e}^{+}\right)<1.6×{10}^{-7}$, and, for both decays combined, $B\left({B}^{0}\to {K}^{*0}{\mu }^{±}{e}^{\mp }\right)<1.8×{10}^{-7}$. These are the most stringent limits on these decays to date.

Published in: Physical Review D 98 (2018)