Search for $B^{0} to tau^pm ell^mp$ ($ell=e,mu$) with a hadronic tagging method at Belle

We present a search for the lepton-flavor-violating decays $B^{0} to tau^pm ell^mp$, where $ell=(e,,mu)$, using the full data sample of $772 times 10^6$ $B overline{B}$ pairs recorded by the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. We use events in which one $B$ meson is fully reconstructed in a hadronic decay mode. The $tau^pm$ lepton is reconstructed indirectly using the momentum of the reconstructed $B$ and that of the $ell^mp$ from the signal decay. We find no evidence for $B^{0} to tau^pm ell^mp$ decays and set upper limits on their branching fractions at 90% confidence level of $cal B$($B^{0} to tau^pm mu^{mp}$)$ < 1.5 times 10^{-5}$ and $cal B$($B^{0} to tau^pm e^{mp}$)$ < 1.6 times 10^{-5}$.