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arXiv 0710.4974hep-ex
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B^0-->(rho pi)^0含时Dalitz分析中CP不对称性和分支分数的测量及夸克混合角φ_2的限制

Measurement of CP Asymmetries and Branching Fractions in a Time-Dependent Dalitz Analysis of B^0-->(rho pi)^0 and a Constraint on the Quark Mixing Angle phi_2

The Belle Collaboration, A. Kusaka, C. C. Wang

摘要:

我们基于包含449 x 10^6个BB对的414/fb数据样本,给出了B 0--> pi+ pi-pi 0衰变的时间相关Dalitz图分析结果。这些数据是在KEKB非对称能量e+e-对撞机上用Belle探测器在Upperion(4S)共振上收集的。结合我们的分析与带电B衰变模式的信息,我们进行了充分的Dalitz和同位旋分析,并获得了夸克混合角φ_2,68度的约束。< phi_2 <95度。在68.3%置信水平下,phi_2溶液与标准模型(SM)一致。一个大的SM不受欢迎的地区也仍然存在。B 0-> rho ~+-(770)pi ~+和B 0-> rho ~ 0(770)pi ~ 0衰变过程的分支分数为(22.6 ± 1.1[stat.] +- 4.4 [系统])x 10^{-6}和(3.0 +- 0.5 [stat.] +- 0.7 [系统])x 10^{-6}。这些是过程B 0-> rho(770)pi的第一分支分数测量,其中最低共振rho(770)与径向激励明确分离。

英文摘要:

We present the results of a time-dependent Dalitz plot analysis of B0 --> pi+ pi- pi0 decays based on a 414/fb data sample that contains 449 x 10^6 BB pairs. The data was collected on the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric energy e+e- collider. Combining our analysis with information on charged B decay modes, we perform a full Dalitz and isospin analysis and obtain a constraint on the quark mixing angle phi_2, 68deg. < phi_2 < 95deg. at the 68.3% confidence level for the phi_2 solution consistent with the standard model (SM). A large SM-disfavored region also remains. The branching fractions for the decay processes of B0 --> rho+-(770) pi-+ and B0 --> rho0(770) pi0 are measured to be (22.6 +- 1.1[stat.] +- 4.4 [syst.]) x 10^{-6} and (3.0 +- 0.5 [stat.] +- 0.7 [syst.]) x 10^{-6}, respectively. These are the first branching fraction measurements of the process B0 --> rho(770)pi with the lowest resonance rho(770) explicitly separated from the radial excitations.

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