Search for the rare decay $D^0togammagamma$ at Belle

We search for the rare radiative decay $D^0togammagamma$ using a data sample with an integrated luminosity of $832{rm fb^{-1}}$ recorded by the Belle detector at the KEKB $e^+e^-$ asymmetric-energy collider. We find no statistically significant signal and set an upper limit on the branching fraction of ${cal B}(D^0togammagamma)<8.5times10^{-7}$ at $90%$ confidence level. This is the most restrictive limit on the decay channel to date.