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

中性B介子系统中混合引起的CP破坏的研究

• 批准号: 09246102
• 负责人: AIHARA Hiroaki
• 金额: $ 123.26万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research on Priority Areas (A)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09246102/
• 关键词: B Meson; CP violation; B factory; Solid-state detector; 素粒子; 対称性; ピクセル検出器; 小林・益川理論; 集積回路; 超対称標準理論; 位置検出器

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.

1.中性B介子系统中CP破坏的观测：基于一个包含3130万个B-反B对的29.1FB^~(-1)数据样本，我们观察到中性B介子系统中的CP破坏。一个中性B介子被完全重建，伴随的B介子的味道由它的衰变产物确定。从两个B介子衰变点之间时间间隔分布的对称性出发，我们测量了标准模型的CP破坏参数Sin_2φ_1=0.99±0.14±0.06。这种测量是通过使用我们团队建造和操作的高精度硅顶点探测器来实现的。我们还充分利用了用授权构建的多CPU服务器。这一违反CP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为下一代顶点探测器开发传感器和读出IC。我们成功地研制了一种新型硅片传感器和一种耐辐射读出集成电路。利用我们的研发成果，我们已经完成了探测器的设计，并开始建造最终的装置。

项目成果

H. Aihara: "The BELLE Silicon vertex detector"Nucl. Instr. Meth.. A 46. 268 (2001)

H. Aihara：“BELLE 硅顶点探测器”Nucl。

M. Yokoyama et al.: "Radiation Hardness of VA1 fabricated with Submicron Process Technology"IEEE Trans. Nucl. Sci.. 48. 440 (2001)

M. Yokoyama 等人：“采用亚微米工艺技术制造的 VA1 的辐射硬度”IEEE Trans。

H. Aihara: "Prospects with the BELLE Detector"Proceeding of the XI Symposium on Hadron Collider Physics. 1. 130-136 (1997)

H. Aihara：“BELLE 探测器的展望”第十一届强子对撞机物理研讨会论文集。

R. Abe et al.: "Performance of the Belle Silicon Vertex Detector"IEEE Trans. Nucl. Sci.. 48. 997 (2001)

R. Abe 等人：“Belle 硅顶点检测器的性能”IEEE Trans。

T.E.Browder et al.: "Pixel Detectors For B-Factories" Proceedings of International Pixel Detector Workshop. 1. 42-48 (1998)

T.E.Browder 等人：“B-Factories 的像素探测器”国际像素探测器研讨会论文集。