| Project/Area Number |
15340087
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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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 | High Energy Accelerator Research Organization (2004)
The High Energy Accelerator Research Organization (2003) |
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Principal Investigator |
NAGAE Tomofumi High Enerfy Accelerator Research Institute, J-PARC Project Office, Professor, 大強度陽子加速器計画推進部, 教授 (50198298)
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| Co-Investigator(Kenkyū-buntansha) |
NOUMI Hiroyuki High Energy Accelerator Research Organization, Institute of Partide and Nuclear Studies, Associate Professor, 素粒子原子核研究所, 助教授 (10222192)
SEKIMKOTO Michiko High Energy Accelerator Research Organization, Institute of Partide and Nuclear Studies, Research Associate, 素粒子原子核研究所, 助手 (50206637)
OUTA Haruhiko RIKEN, RIKEN Disovery Reseach Institute, Chief Scientist, 中央研究所, 先任研究員 (60221818)
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| Project Period (FY) |
2003 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥14,700,000 (Direct Cost: ¥14,700,000)
Fiscal Year 2004: ¥5,600,000 (Direct Cost: ¥5,600,000)
Fiscal Year 2003: ¥9,100,000 (Direct Cost: ¥9,100,000)
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| Keywords | Hypernuclei / Strangeness |
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| Research Abstract |
The hypernuclear data on ^6Li, ^7Li, ^<12>C, ^<27>Al, and ^<51> V targets were accumulated during the fast data taking period from October 2003 to March 2004 with the FINUDA detector system at the DAFNE Φ-Factory in Italy The integrated luminosity of 250 pb^<-1> was delivered as scheduled. Almost mono-chromatic K- beam at 16 MeV produced from the ΦK^-K^+ decay was stopped in the very thin (〜200 mg/cm^2) targets. All the data were brought back to Japan and analyzed independently from the Italian collaborators. Calibrations for each detector have been in progress. Although the position resolutions of the tiadking chambers are still not at the optimum values, the calibration peaks corresponding to the K_<μ2> and K_<π2> decays gave us the correct momenta and reasonably good momentum resolutions. We expect the resolution could be further improved in the future analysis. As for the (K^-_<stop>,π^-) reaction spectroscopy, we have obtained ^<12>_ΛC excitation energy spectrum with the energy resolution of 1.45 MeV FWHM. This is as good as so-far the best energy resolution achieved it the world. A few peak structures were observed for the first time. Even for the heavier targets, events were observed in the bound region. We expect several excited states to be resolved in the future analysis.
Λ hyperons in the (K^-_<stop>,π^-) reactions were successfully detected in the FINUDA detector from the invariant mass distribution of proton mid π^-. Further we have observed a Λ hyperon accompanied by a proton emitted in the back to-back direction. The invariant mass distribution of the Λ-proton pair indicates that they are coning out from a K_-pp bound system. The binding energy of the system was found to be〜115 MeV. This value is very large as compared to the normal nuclear binding and might imply a possible formation of high density nuclear environment in the system. Production of Σ hypernuclei was also searched by tagging the Λ hyperon from a strong conversion process ΣN→ΛN.
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