分类: 物理学 >> 核物理学 提交时间: 2016-08-26
摘要: We present a search for a non-Standard-Model invisible particle X0 in the mass range 0.1-1.8GeV/c2 in B+→e+X0 and B+→μ+X0 decays. The results are obtained from a 711 fb−1 data sample that corresponds to 772×106BB¯ pairs, collected at the Υ(4S) resonance with the Belle detector at the KEKB e+e− collider. One B meson is fully reconstructed in a hadronic mode to determine the momentum of the lepton of the signal decay in the rest frame of the recoiling partner B meson. We find no evidence of a signal and set upper limits on the order of 10−6.