We report the measurement of the direct CP asymmetry in the radiative ¯B→Xs+dγ decay using a data sample of (772±11)×106 B¯B 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.
Physical Review Letters
Digital Object Identifier (DOI)
Pesántez et al, L., "Measurement of the Direct CP Asymmetry in ¯B→Xs+dγ Decays with a Lepton Tag" (2015). Faculty Publications. 3961.