| Project/Area Number |
18204019
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Particle/Nuclear/Cosmic ray/Astro physics
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| Research Institution | The University of Tokyo |
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Principal Investigator |
AIHARA Hiroaki The University of Tokyo, 大学院・理学系研究科, 教授 (60167773)
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| Co-Investigator(Kenkyū-buntansha) |
岩崎 昌子 東京大学, 大学院・理学系研究科, 助教 (70345172)
角野 秀一 東京大学, 素粒子物理国際研究センター, 助教 (70376698)
羽澄 昌史 大学共同利用機関法人高エネルギー加速器研究機構, 素粒子原子核研究所, 准教授 (20263197)
幅 淳二 大学共同利用機関法人高エネルギー加速器研究機構, 素粒子原子核研究所, 教授 (60180923)
坪山 透 大学共同利用機関法人高エネルギー加速器研究機構, 素粒子原子核研究所, 助教 (80188622)
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| Co-Investigator(Renkei-kenkyūsha) |
IWASAKI Masako 東京大学, 大学院・理学系研究科, 講師 (70345172)
KAKUNO Hidekazu 東京大学, 素粒子物理国際研究センター, 助教 (70376698)
HAZUMI Masashi 大学共同利用機関法人高エネルギー加速器研究機構, 素粒子原子核研究所, 教授 (20263197)
HABA Junji 大学共同利用機関法人高エネルギー加速器研究機構, 素粒子原子核研究所, 教授 (60180923)
TSUBOYAMA Toru 大学共同利用機関法人高エネルギー加速器研究機構, 素粒子原子核研究所, 講師 (80188622)
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| Project Period (FY) |
2006 – 2009
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| Project Status |
Completed (Fiscal Year 2009)
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| Budget Amount *help |
¥48,880,000 (Direct Cost: ¥37,600,000、Indirect Cost: ¥11,280,000)
Fiscal Year 2009: ¥7,150,000 (Direct Cost: ¥5,500,000、Indirect Cost: ¥1,650,000)
Fiscal Year 2008: ¥10,010,000 (Direct Cost: ¥7,700,000、Indirect Cost: ¥2,310,000)
Fiscal Year 2007: ¥10,400,000 (Direct Cost: ¥8,000,000、Indirect Cost: ¥2,400,000)
Fiscal Year 2006: ¥21,320,000 (Direct Cost: ¥16,400,000、Indirect Cost: ¥4,920,000)
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| Keywords | 素粒子物理 / Bファクトリー / B中間子 |
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| Research Abstract |
We measured CP violating asymmetries in the neutral B meson decaying to KOsK+K-. It was based on a data sample containing 657 million B-antiB pairs. By employing the time-dependent Dalitz plot analysis to the BO decays with KOsK+K- final state, we successfully measured the CP-violating phases in each significant decay amplitude taking into account the interferences between them and resolved two-fold ambiguity in the weak phases that arises in quasi-two-body time-dependent CP analyses. Evidence for CP violation at a significance of 3.9σ is found in the BO->φKOs decay and the result is consistent with the Standard Model expectation. We also made a precise measurement of the branching fraction for a flavor-changing neutral current decay B→Xsl+l-, where Xs is a hadronic system containing an s-quark and l is an electron or a muon. The results are the most precise measurements to date.
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