Observation of the decay $B_s^0\rightarrow K^0\overlineK^0$

摘要: We measure the decay B0s→K0K¯¯¯¯¯0 using data collected at the Υ(5S) resonance with the Belle detector at the KEKB e+e− collider. The data sample used corresponds to an integrated luminosity of 121.4 fb−1. We measure a branching fraction B(B0s→K0K¯¯¯¯¯0)=[19.6+5.8−5.1(stat.)±1.0(sys.)±2.0(NB0sB¯¯¯¯0s)]×10−6 with a significance of 5.1 standard deviations. This measurement constitutes the first observation of this decay.