分类: 物理学 >> 核物理学 提交时间: 2016-09-07
摘要: We report the measurement of the direct CP asymmetry in the radiative B¯→Xs+dγ decay using a data sample of (772±11)×106 BB¯ pairs collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e− collider. The CP asymmetry is measured as a function of the photon energy threshold. For E∗γ≥2.1 GeV, where E∗γ is the photon energy in the center-of-mass frame, we obtain ACP(B¯→Xs+dγ)=(2.2±3.9±0.9)%, consistent with the Standard Model prediction.