2001 Fiscal Year Final Research Report Summary
Study of Mixiing-induced CP Violation in the Neutral B Meson System
| Project/Area Number |
09246102
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| Research Category |
Grant-in-Aid for Scientific Research on Priority Areas (A)
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| Allocation Type | Single-year Grants |
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| Research Institution | The University of Tokyo |
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Principal Investigator |
AIHARA Hiroaki the University of Tokyo, Graduate School of Science Professor, 大学院・理学系研究科, 教授 (60167773)
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| Co-Investigator(Kenkyū-buntansha) |
HARA Takanori Osaka University, Graduate School of Science Reserch Associate, 大学院・理学研究科, 助手 (70283827)
HAZUMI Masashi High Energy Accelerator Reserch Organization, Associate Professor, 助教授 (20263197)
TAJIMA Hiroyasu the University of Tokyo, International Center for Elementary particle Physics, Reserche Associate, 助手 (80222107)
WATANABE Yasushi Tokyo Institute of Technology, Faculty of Science Professor, 大学院・理工学研究科, 教授 (40126199)
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| Project Period (FY) |
1997 – 2000
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| Keywords | B Meson / CP violation / B factory / Solid-state detector |
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| Research Abstract |
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.
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