Study of Mixiing-induced CP Violation in the Neutral B Meson System

1.中性B介子系统CP破坏的观测：利用29.1fb ^<-1>的3130万个B-反B对的数据样本，我们观测到了中性B介子系统的CP破坏。一个中性B介子被完全重建，伴随的B介子的味道被确定从它的衰变产物。根据两个B介子衰变点之间时间间隔分布的对称性，我们测量了标准模型CP破坏参数sin 2 φ_1=0.99±0.14±0.06。这种测量是通过使用我们小组建造和操作的高精度硅顶点探测器实现的。我们还充分利用了多CPU服务器建设的赠款。这种CP破坏的观察标志着第一个目标的实现。完成下一代硅顶点探测器的研发：该项目的第二个目标是开发下一代顶点探测器的传感器和读出IC。我们成功地研制了一种新型的硅条传感器和一种抗辐射读出集成电路。利用我们的研发成果，我们已经完成了探测器的设计，并开始建造最终设备。

1. Observation of CP violatin in the neutral B meson system : Based on a 29.1 fb^<-1> data sample which contains 31.3 million B-anti B pairs, we have observed CP violation in the neutral B meson system. One neutral B meson is fully reconstructed and the flavor of the accompanying B meson is determined from its decay products. From the symmetry in the distribution of the time intervals between the two B meson decay points, we measure the Standard Model CP violation parameter sin2φ_1=0.99±0.14±0.06. This measurement is made possible by the use of the high-precision silicon vertex detector, which our group constructed and operated. We have also made full use of multi-CPU server constructed with the grant. This observation of CP violation marks the achievement of the first goal.2. Completion of R＆D of the next-generation silicon vertex detector : The second goal of the project was to develop sensors and read-out Ics for the next-generation vertex detector. We have successfully developed both a new-type of silicon strip sensors and a radiation-hard Ics for readout. Taking advantage of our R＆D results, we have finished the design of the detector and started construction of the final device.