Search for the rare decay $D^0\to\gamma\gamma$ at Belle

摘要: We search for the rare radiative decay D0→γγ using a data sample with an integrated luminosity of 832fb−1recorded 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 B(D0→γγ)<8.5×10−7 at 90% confidence level. This is the most restrictive limit on the decay channel to date.