Search for B 0 decays to invisible final states ( + γ ) at Belle

Abstract

We report searches for B0→invisible and B0→invisible+γ decays, where the energy of the photon is required to be larger than 0.5 GeV. These results are obtained from a 711 fb-1 data sample that contains 772×106BB¯ pairs and was collected near the ϒ(4S) resonance with the Belle detector at the KEKB e+e- collider. We observe no significant signal for either decay and set upper limits on their branching fractions at 90% confidence level of B(B0→invisible)<7.8×10-5 and B(B0→invisible+γ)<1.6×10-5.