| Project/Area Number |
63460014
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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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 | KYOTO UNIVERSITY |
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Principal Investigator |
IMAI Kenichi Kyoto Univ.Physics Professor, 理学部, 教授 (70025493)
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| Co-Investigator(Kenkyū-buntansha) |
ENYO Hideto Kyoto Univ.Physics Instructor, 理学部, 助手 (30213606)
MASAIKE Akira Kyoto Univ.Physics Professor, 理学部, 教授 (40022587)
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| Project Period (FY) |
1988 – 1989
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| Project Status |
Completed (Fiscal Year 1989)
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| Budget Amount *help |
¥8,500,000 (Direct Cost: ¥8,500,000)
Fiscal Year 1989: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 1988: ¥7,000,000 (Direct Cost: ¥7,000,000)
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| Keywords | Hyperon / Emulsion / Hybrid detector / H-dibaryon / Hypernuclei / エマルジョン / ハイブリッド検出器 / ハイパ-核 / Hーダイバリオン |
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| Research Abstract |
The purpose of this research project is to study low-energy hyperon nucleus reaction with an emulsion-counter hybrid method. The experiment was carried out at KEK to search for nuclei with S=-2 and the H-dibaryon. The (K^-, K^+) reaction from emul13EA\ : sion nuclei and the XI^- hyperon capture by nuclei following the stopped HI^- in the emulsion were studied in detail. The statistics of the (K^-, K^+) reaction and stopped HI^- have been improved by a factor of hundred over those of old emulsio13EA\ : n experiments.
The main results are summarized as follows. 1) The weak decay of nuclei with S=-2 has been confirmed by the following observations ; a) Several hyperfraqments from HI^- capture show sequential weak decay topology which is characteristic of double h13EA\ : hpernuclei. b) The distribution of total visible energy-release and the rate of emission of more than two fast protons, after HI^- capture by heavy nuclei in the emulsion, indicate the sequential weak decay of nuclei with S=-2.2) The observation o13EA\ : f nuclei with S=-2 places a strong limitation on the possible H mass. Especially, one of the events limits the H mass to be larger than 2203.7 +- 0.7 MeV/c^2.3) Through the observation of two single hypernuclei after HI^- capture at rest, two (HI13EA\ : ^--^<12>C) systems, atom or nucleus, are clearly identified for the first time. 4) We searched for the H-dibaryon both in the K^+ momentum spectrum and in the emulsion near the HI^- stopping points, and obtained upper limits for the production of the H.5) The systematics of the (K^-, K^+) reaction and HI^- hyperon capture by nuclei were studied for the first time.
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