| Project/Area Number |
10044086
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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 |
素粒子・核・宇宙線
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| Research Institution | Osaka University |
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Principal Investigator |
KISHIMOTO Tadafumi Graduate School of Science, 0saka University, Professor, 大学院・理学研究科, 教授 (90134808)
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| Co-Investigator(Kenkyū-buntansha) |
TAMURA Keisuke Fukui Medical Colledge Associate Professor, 助教授 (30212046)
SAKGUCHI Atsushi Graduate School of Science, Osaka University, Associate Professor, 大学院・理学研究科, 助教授 (70205730)
MAEDA Kazushige Dep. of Phys., Tohoku Univ. Associate Professor, 大学院・理学研究科, 助教授 (20125652)
AJIMURA Shuhei Graduate School of Science, Osaka University Reaearch Associate, 大学院・理学研究科, 助手 (10273575)
NOUMI Hiroyuki IPNS KEK Reaearch Associate, 助手 (10222192)
応田 治彦 高エネルギー加速器研究機構, 助手 (60221818)
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| Project Period (FY) |
1998 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥5,400,000 (Direct Cost: ¥5,400,000)
Fiscal Year 1999: ¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1998: ¥3,300,000 (Direct Cost: ¥3,300,000)
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| Keywords | Hypernuclei / Strangeness / Weak nonmeonic decay / Spin-orbit interaction / Baryon-Baryon Interaction / Short Range correlation / Quark degeree of freedom / バリオン間相互作用 / ハイペロン |
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| Research Abstract |
It is well known that hadrons (Baryons and mesons) are made up of quarks and gluons by the strong interaction. The interaction among hadrons is not well understood especially due to our inability to describe the quark confinement beased on a known principle. The nucleon interaction is well described by meson exchange theory except at short distances where size of hadrons has to be taken into account in the model. Quark and gluon degrees of freedom have to be present though flexibility of the meson change model forbits to pin down clearly the existence of the freedom. The SU (3) extention of the model should be the best testing gound for many models that describe well the NN interaction. In the present research we forcused our attention to the phenomena which originate short range interaction. Following subjects were studied in this research.
(1) Spin-orbit interaction ofィイD313(/)ΛィエD3C was measured.
Spin-orbit splitting of Λ hypernuclei is known to be small though no definite value has been given by experiments. We produced ィイD313(/)ΛィエD3C by the (K-, π-) using kaon beam provied by the AGS at BNL and measured the splitting by detecting γ rays. The splitting was found to be 20-40 times smaller than that of nucleons.
(2) Parity violation in the weak nonmesonic decay of hypernuclei.
Weak nonmesonic decay NΛ→NN has a large momentum transfer that make interaction at short distance vital. We demonstrated production of polarized Λ hypernuclei and weak nonmesonic decay has asymmetric angular distribution corresponding parity violation. The magnitude of the parity violation is found to be inconsistent with meson exchange model. As for the further study we are preparing an experiment to measure the inverse reaction (pn→pΛ) of the weak nonmesonic decay. It is a process to produce strangeness by weak interaction. It has never been challenged. We found that the experiment is feasible by carefully desining the detector.
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