| Project/Area Number |
13640307
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
素粒子・核・宇宙線
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| Research Institution | High Energy Accelerator Research Organization (2004)
The High Energy Accelerator Research Organization (2001-2003) |
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Principal Investigator |
ABE Kazuo High Energy Accelerator Research Organization, Institute of Particle and Nuclear Studies, professor, 素粒子原子核研究所, 教授 (80167931)
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| Co-Investigator(Kenkyū-buntansha) |
SAKAI Yoshihide KEK, IPNS, professor, 素粒子原子核研究所, 教授 (90170571)
佐川 宏行 高エネルギー加速器研究機構, 素粒子原子核研究所, 助手 (80178590)
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| Project Period (FY) |
2001 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥3,300,000 (Direct Cost: ¥3,300,000)
Fiscal Year 2004: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2003: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2002: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2001: ¥1,000,000 (Direct Cost: ¥1,000,000)
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| Keywords | CP violation / B meson / CPT symmetry / particle mixing / 素粒子物理学 / 反粒子 / 中間子の混合 / CP非保存 |
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| Research Abstract |
1. B0-B0bar mixing parameter was measured using several different methods. The method which uses semileptonic decays gave result of 0.503+-0.008+-0.010. Here the unit is an inverse of pico second and the errors are statistical and systematic, respectively. The method which uses hadronic decays gave 0.528+-0.017+-0.011. Several other method were also tried. All results are consistent with each other. These results made essential contributions to the determination of world average of the mixing parameter.
2. Possible CPT violation in B0B0bar mixing phenomenon was searched using semi leptonic decay events. Our conclusion is that if such unusual phenomenum exists, it is less than 10% level. This is the first upper limit for such exotic effect in the B meson system.
3. We seached for CP violation in the B0 B0bar mixing using semileptonic events. The result expressed in terms of a parameter called epsilon B is -0.0003+-0.0020+-0.0017, which is consistent with being zero and the most stringent upper limit up to now. According to the Standard Model, this should be less than 0.001. Therefore our result is consistent with the Standard Model.
4. A CP violation parameter called sin(2phil+phi3), which is expected to occur in the decay of neutral B meson into D^* meson and pi meson was measured. Our result is consistent with being zero within 6% statistical error. Although the result is not statistically significant yet, we believe the data analysis method for this approach was established.
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