| Project/Area Number |
03041087
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| Research Category |
Grant-in-Aid for international Scientific Research
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| Allocation Type | Single-year Grants |
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| Section | Field Research |
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| Research Institution | National Laboratory for High Energy Physics (KEK) |
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Principal Investigator |
SHIMIZU Yoshimitsu National Laboratory for High Energy Physics, 物理研究部, 教授 (20011744)
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| Co-Investigator(Kenkyū-buntansha) |
TOBIMATSU Keijirou Kogakuin University, 工学部, 講師 (40237102)
近 匡 成蹊大学, 工学部, 助手 (90215442)
YAZAKI Shigeo Kitazato University, 教養部, 教授 (10011743)
JIMBO Masato Tokyo Management College, 経営情報学科, 助教授 (10226392)
IGARASHI Masataka Tokai University, 理学部, 教授 (90147116)
ISHIKAWA Tadashi National Laboratory for High Energy Physics, データ処理センター, 助手 (90184481)
KURIHARA Yoshimasa National Laboratory for High Energy Physics, 物理研究部, 助手 (50195559)
FUJII Keisuke National Laboratory for High Energy Physics, 物理研究部, 助手 (30181308)
MIYAMOTO Akiya National Laboratory for High Energy Physics, 物理研究部, 助手 (50174206)
FUJIMOTO Junpei National Laboratory for High Energy Physics, 物理研究部, 助手 (90202291)
HIKASA Ken-ichi Tohoku University, 理学部, 助教授 (20208739)
HAGIWARA Kaoru National Laboratory for High Energy Physics, 物理研究部, 助手 (50189461)
HIGASHIJIMA Kiyoshi National Laboratory for High Energy Physics, 物理研究部, 助教授 (10092313)
KAWABATA Setsuya National Laboratory for High Energy Physics, 物理研究部, 助教授 (40152996)
KON Tadashi Seikei University
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| Project Period (FY) |
1991 – 1992
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| Keywords | Electron-positron annihilation / Standard model in particle physics / Radiative corrction in electro-weak theory / QCD parton shower / Automatic calculation of Feynman amplitude / Higgs particle / Supersymmetric model |
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| Research Abstract |
The prompt photon production process is observed in LEP experiments. We have examined the process e^+e^-*qqgamma including one-loop QCD correction. This research is done using different regularization method by Japanese group by French group.
In LEP experiments, events with two leptons and two photons are observed, which are suspected to be a new phenomenon. By use of GRACE system, the system to generate Feynman diagrams and to generate matrix elements for a corresponding process,we have calculated the cross section for e^+e^-*ll^^-gammagamma in electro-weak theory, whether the events are conventional ones based on the higher order QED interaction. Though the experimental signal exceeds the above background expectations, the origin of these is still uncertain due to the experimental controversy.
Using the GRACE system, we have done systematic computation of the processes with three- and four-particle final states in high energy e^+e^- experiments, e.g., LEPH, JLC and so forth.
The estimation of the strong coupling constant is done by studying experimental data by the parton shower model NLLjet and by the analytic calculation including resummation.
The formulation of QED parton shower is done, so that the decoration of higher order QED correction for an arbitrary elementary process becomes possible.
The numerical method developed for one-loop amplitude is also extended to multi-loop case.
A new system for the symbolic manipulation is developed It has the feature to contract the expressions which appear in the calculation in particle physics.
Some processes including the production of the super-particles are studied and the possible signal expected in the future colliders is shown.
To execute the phase space integration efficiently, a new method for the numerical integration is investigated.
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