Measurement of CP observables in B+- --> D_CP K+- decays and constraints on the CKM angle gamma
Measurement of CP observables in B+- --> D_CP K+- decays and constraints on the CKM angle gamma
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DOI：
10.1103/physrevd.82.072004
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发表时间：
2010-07
影响因子：
5
通讯作者：
The Babar Collaboration;P. Sanchez;et al.
中科院分区：
文献类型：
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作者：
The Babar Collaboration;P. Sanchez;et al.
利用SLAC的PEP-Ⅱ非对称能量B工厂的BaBar探测器收集的4.67亿个Y（4S）--> BB巴衰变的全部样品，我们对B+- -> DK+衰变进行了“GLW”分析，使用的衰变模式是中性D介子衰变到CP本征态或非CP本征态。我们测量了CP-偶和CP-奇D末态的部分衰变率电荷不对称性分别为A_CP+ = 0.25+-0.06+-0.02和A_CP- = -0.09+-0.07+-0.02，其中第一个误差是统计误差，第二个误差是系统不确定度。参数A_CP+不同于零，具有3.6标准差的显著性，构成直接CP违反的证据。我们还测量了电荷平均B部分衰变率在CP和非CP衰变中的比值，R_CP ~+ = 1.18+-0.09+-0.05和R_CP ~- = 1.07+-0.08+-0.04。我们推导出（db）么正三角形的角度γ、强相位差δ_B和振幅比r_B的频率置信区间，它们与B-> DK-衰减振幅相关，公式为r_Be^{i（δ_B-gamma）} = A（B-> anti-D 0 K^-）/A（B-> D 0 K-）。考虑到统计和系统不确定性，我们得到0.24<r_B<0.45（0.06<r_B<0.51），并且模180度，11.3度<伽玛< 22.7度或80.9度<伽玛< 99.1度或157.3度<伽玛< 168.7度（7.0度<伽马< 173.0度），置信水平为68%（95%）。
Using the entire sample of 467 million Y(4S) --> BBbar decays collected with the BaBar detector at the PEP-II asymmetric-energy B factory at SLAC, we perform a "GLW" analysis of B+- --> D K+- decays, using decay modes in which the neutral D meson decays to either CP-eigenstates or non-CP-eigenstates. We measure the partial decay rate charge asymmetries for CP-even and CP-odd D final states to be A_CP+ = 0.25+-0.06+-0.02 and A_CP- = -0.09+-0.07+-0.02, respectively, where the first error is the statistical and the second is the systematic uncertainty. The parameter A_CP+ is different from zero with a significance of 3.6 standard deviations, constituting evidence for direct CP violation. We also measure the ratios of the charged-averaged B partial decay rates in CP and non-CP decays, R_CP+ = 1.18+-0.09+-0.05 and R_CP- = 1.07+-0.08+-0.04. We infer frequentist confidence intervals for the angle gamma of the (db) unitarity triangle, for the strong phase difference delta_B, and for the amplitude ratio r_B, which are related to the B- --> DK- decay amplitude by r_Be^{i(delta_B-gamma)} = A(B- --> anti-D0 K^-)/A(B- --> D0 K-). Including statistical and systematic uncertainties, we obtain 0.24<r_B<0.45 (0.06<r_B<0.51) and, modulo 180 degrees, 11.3 degrees < gamma < 22.7 degrees or 80.9 degrees < gamma < 99.1 degrees or 157.3 degrees < gamma < 168.7 degrees (7.0 degrees < gamma < 173.0 degrees) at the 68% (95%) confidence level.