Search for $D^{0}$ decays to invisible final states at Belle
  We report the result from the first search for $D^0$ decays to invisible final states. The analysis is performed on a data sample of 924 $\rm{fb}^{-1}$ collected at and near the $\Upsilon(4S)$ and $\Upsilon(5S)$ resonances with the Belle detector at the KEKB asymmetric-energy $e^{+}e^{-}$ collider. The absolute branching fraction is determined using an inclusive $D^0$ sample, obtained by fully reconstructing the rest of the particle system including the other charmed particle. No significant signal yield is observed and an upper limit of $9.4\times 10^{-5}$ is set on the branching fraction of $D^0$ to invisible final states at 90\% confidence level. 
Y.-T. Lai, M.-Z. Wang, I. Adachi, H. Aihara, S. Al Said, D. M. Asner,   T. Aushev, R. Ayad, I. Badhrees, A. M. Bakich, V. Ba...
hep-ex