2001 Fiscal Year Final Research Report Summary
Study of Direct CP Violation
| Project/Area Number |
09246104
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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 | Nagoya University |
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Principal Investigator |
OHSHIMA Takayoshi Nagoya University, Department of Physics Professor, 大学院・理学研究科, 教授 (00134651)
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| Co-Investigator(Kenkyū-buntansha) |
TAKAHASHI Tamotsu Osaka-city Univ. Dep. of Physics, Prof., 理学部, 教授 (20047137)
NOGUCHI Seishi Nara Women Univ. Dep. of Physics, Prof., 理学部, 教授 (90093559)
SUZUKI Shiro Nagoya Univ. Dep. of Physics Ass. Prof., 大学院・理学研究科, 助教授 (50089851)
NITOH Osamu Tokyo Univ. of Agriculture and Technology, Dep. Of Applied Physics, Ass. Prof., 工学部, 助教授 (00189333)
SUMIYOSHI Takayuki High Energy Accelerator Reserch Organization, Institute of Particle and Nuclear Studies, Ass. Prof., 素粒子原子核研究所, 助教授 (30154628)
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| Project Period (FY) |
1997 – 2000
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| Keywords | Direct CP Violation / Kobayashi-Maskaa Matrix / φ_3 CP-Angle / T-lepton's CP Vidaton / Partide Identification / Cherenkov Radiation |
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| Research Abstract |
1. Physics reserch for Direct CP Violation
Studies of direct CP violation in B-meson decays has been progressed along with accumulation of data at KEKB/Belle experiment. We succeeded to identify B→DK, D^*K, Dπ and D^*π sugbaks sebsutuve ti φ_3 angle in KM CP-triangle and measured their branching ratios. The CP asymmetry in B→Kp decay is also observed as -0.22<A_<CP>(B^0→Kπ^±+Kπ^0)<0.25. We have looked for a signal of new physics in rae B-meson decays and the branching ratio of B→Kηηwas mesured for the first time as (0.99±0.36±0.12)×10^<-6>.
Concerning to tau-lepton physics, we have examined a violation of CP/T invariance in ters of tau's EDM and resulted in a ten times higher sensitivity than previous measurement as dπ < 2×10^<-7>e ・ cm. We also looked for lepton flavor violation π→μγ decay and reached to the most sensitive upper-limit of 1.0×10^<-6>.
In the final year, we have organized the international conference of "B Physics and CP Violation (BCP4)" at Ise, Shima, and reported and discussed our outcomes from this project. In 2001 we have held a symposium "The Lost AntiWorld" under the 『University and Science』 public lecture series managed by NEXT at sendai to report our reserch to public. The both meeting were carried out quite successfully.
2. R＆D for new detectors
We, Nagoya group, invented a new type of ring imaging Cherenkov counter named as TOP counter, and studied its basic performances. A silica aerogel RICH detector and a Gas cherenkov counter were examined by KEK group and Osaka-city group, respectively. Using test pulsers and beams the basic properties of these detectors were investigated.
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