Possible Existence of Sigma-Hypernuclei
| Project/Area Number |
02804010
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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 | University of Tokyo (1992)
Hokkaido University (1990-1991) |
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Principal Investigator |
AKAISHI Yoshinori University of Tokyo, Institute for Nuclear Study, Professor, 原子核研究所, 教授 (50001839)
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| Project Period (FY) |
1990 – 1992
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| Project Status |
Completed (Fiscal Year 1992)
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| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1992: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1991: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1990: ¥600,000 (Direct Cost: ¥600,000)
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| Keywords | Strangeness / Hypernucleus / Sigma-particle / Hyperon / Baryon-baryon interaction / ハイパ-核 / ケイオン |
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| Research Abstract |
In 1980 the observation of narrow peaks due to the SIGMA production were reported at CERN.The widths are about 8 MeV, which are unexpectedly narrow compared to anticipating theoretical predictions of 20-30 MeV.In spite of many theoretical efforts it still remains a puzzle why such narrow peak structure exists in the SIGMA-continuum region. In order to confirm the existence of SIGMA-hypernuclei, more decisive data should be supplied. We indicated theoretically the possible existence of ^4_MAHand ^4_MAHe below the SIGMA-emission threshold on the basis of four-body calculations with realistic SIGMAN interaction.
In 1989 Hayano et al.presented an evidence of the bound SIGMA-hypernucleus. They observed ^4_MAHe, below the threshold by 3.2 MeV with width of 4.6 MeV at KEK.Its energy and width are in good agreement with our theoretical values.
"Is there a bound ^4_MAHe? " This is a question raised by Dalitz. Unfortunately some ambiguities remain at present in the experimental analysis of the stopped K^-data. The in-flight K^-experiment could presently be the best way to definitely answer the above question.
It is interesting and significant to look for SIGMA-hypernuclear states in various nuclei other than ^4_MAHe. We constructed the nucleus-SIGMA potential for ^<208>Pb and investigated its characteristic features. Then we indicate the possible existence of SIGMA-hypernuclear states with narrow width even in the heavy nucleus. There can appear a peculiar state, a Coulomb-assisted hybrid state, as a result of the cooperation of Coulomb, centrifugal and strong interactions.
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Report
(4 results)
Research Products
(21 results)
