1993 Fiscal Year Final Research Report Summary
Roles of Instantons in the Low Energy QCD
| Project/Area Number |
04640288
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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 | Tokyo Institute of Technology |
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Principal Investigator |
OKA Makoto Tokyo Institute of Technology, Physics, Associate Professor, 理学部, 助教授 (60144606)
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| Project Period (FY) |
1992 – 1993
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| Keywords | Quantum Chromodynamics / Quark / Gluon / Instanton / Quark Model / Baryonic Interaction / H Dibaryon / Strangeness |
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| Research Abstract |
This research aims at the study of properties and effects of the instanton induced interaction, which comes from te coupling of light quarks to the QCD instanton solution. We pointed out that the instanton induced interaction has a distinctive color-flavor structure and thus shws a different spin-flavor dependences from the perturbatve gluon exchange nteraction. We proposd that a part of the gluon exchange force in the baryon spectrum is in fact the instanton induced interaction and then some of the difficulties that the quark model fces can be solved.
This interaction gives a distinctive features in the baryon-baryn interactions at short distances. According to the quark cluster model calculation, the instanton induced interaction yields a new attractive force between two nuceons. Furthermore, the H dibaryon system receives a strong repulsion due to the three-body part of the instanton induced interaction. We conclude that the H dibaryon may not show as a deep bound state below the two lambda threshould. We studied the effects of the instanton indeuced interaction in other dibaryon systems.
The P-wave baryon spectrum, the spin-orbit force is weak in the nonstrange system, while it gives fair splittings in the strange sector. The short distance NN interactin also requires a strong spin-orbit force among quarks. We pointed out that the spin-orbit force has two origins, the instanton induced interaction and the gluon exchange, which brings the various spin-orbit structures.
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