University of Bonn, 53115 Bonn.
School of Physics, University of Melbourne, Victoria 3010.
Phys Rev Lett. 2015 Apr 17;114(15):151601. doi: 10.1103/PhysRevLett.114.151601. Epub 2015 Apr 15.
We report the measurement of the direct CP asymmetry in the radiative B¯→X(s+dγ) decay using a data sample of (772 ± 11)×10(6) BB[over ¯] 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 Eγ*≥2.1 GeV, where Eγ* is the photon energy in the center-of-mass frame, we obtain A(CP)(B¯→X(s+dγ))=(2.2±3.9±0.9)%, consistent with the standard model prediction.
我们报告了使用 Belle 探测器在 KEKB 对撞机上收集的在 Υ(4S)共振下的 (772 ± 11)×10(6) BB[over ¯]对，对辐射 B¯→X(s+dγ)衰变中的直接 CP 不对称性的测量结果。该 CP 不对称性是作为光子能量阈值的函数来测量的。对于 Eγ*≥2.1 GeV，其中 Eγ*是质心坐标系中的光子能量，我们得到 A(CP)(B¯→X(s+dγ))=(2.2±3.9±0.9)%, 与标准模型预测一致。
