| Project/Area Number |
02804013
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
核・宇宙線・素粒子
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| Research Institution | National Laboratory for High Energy Physics (KEK) |
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Principal Investigator |
NOZAKI Tadao National Laboratory for High Energy Physics, Associate Professor, 物理部, 助教授 (30004469)
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| Co-Investigator(Kenkyū-buntansha) |
ITOH Ryousuke National Laboratory for High Energy Physics, Research Associate, 物理部, 助手 (90193531)
OZAKI Hitoshi National Laboratory for High Energy Physics, Research Associate, 物理部, 助手 (10177214)
UNO Syouji National Laboratory for High Energy Physics, Research Associate, 物理部, 助手 (70183019)
SAGAWA Hiroyuki National Laboratory for High Energy Physics, Research Associate, 物理部, 助手 (80178590)
YAMAUCHI Masanori National Laboratory for High Energy Physics, Associate Professor, 物理部, 助教授 (20174584)
紙谷 琢哉 高エネルギー物理学研究所, 放射光施設, 助手 (20211857)
坪山 透 高エネルギー物理学研究所, 物理部, 助手 (80188622)
玉井 邦雄 高エネルギー物理学研究所, 物理部, 助教授 (60125606)
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| Project Period (FY) |
1990 – 1991
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| Project Status |
Completed (Fiscal Year 1991)
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| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1991: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1990: ¥1,000,000 (Direct Cost: ¥1,000,000)
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| Keywords | B Factory / B Meson / Kobayashi Masukawa model / CP violation / B -> psiK_S / Standard model of elementary particles / Unitary triangle / B.ファクトリ- / B.メゾン / 小林・益川理論 |
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| Research Abstract |
We have studied the B meson physics and the detctor performance expected at the B-Factory at KEK by means of computer simulation techniques. At first an event generator to produce UPSILON(4S) -> BB or UPSILON(5S) -> BB events was made by modifying the LUND event generator. Then a fast detector simulation program was written to simulate effectively the responce of each detector component with high speed. As a result of the simulation study we determined the energies of the electron and positron beams to be 8.0 GeV/c and 3.5 GeV/c, respectively. Also detemined are the requirements for the detector for measuring CP violation effects, which were fully utilized to design the detector.
Then we looked for the ways to decrease the integrated luminosity required for measuring CP violation. As a result we found that there are many channels to be used for CP measurements in addition to the standard channels of B -> psiKs, pipi and Kpi. For example, B -> psiK^*, psi'K_S, x(1^<++>)K_s, D^+D^-, D^<*+>D^<*->, psirho, D^*D, K^*pi, rhopi, api, DK. In particular B -> psiK_L decay can w a good candidate since its contribution amounts to about half of B -> psiK_S. By adding meaurements of these channels the required luminosity could be reduced by at least factor 2. It was also shown that the hadronic decay channels can be used to identify psi. Also shown was that combining B_d -> DK_S and B^<<plus-minus>> -> DK^<<plus-minus>> measurements allows us to measure the third CP angle phi_3 of the unita rity triangle using UPSILON(4S) events. Although the study of the effects of the backgrounds from the continuum events is missing in these analyses the major tasks of this project have been completed.
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