| Project/Area Number |
61540204
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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 | Nagoya University |
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Principal Investigator |
YASUNO Masaru Nagoya University Professor, 理学部, 教授 (30022544)
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| Co-Investigator(Kenkyū-buntansha) |
MIYANISHI Yoshinao Nagoya University Assistant Professor, 理学部, 助手 (50022695)
SAITO Sakae Nagoya University Associate Professor, 理学部, 助教授 (40022694)
SAKAI Kenji Nagoya University Associate Professor, 理学部, 助教授 (70022613)
KANADA Hiroyuki Niigata University Professor, 理学部, 教授 (90022590)
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| Project Period (FY) |
1986 – 1987
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| Project Status |
Completed (Fiscal Year 1987)
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| Budget Amount *help |
¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1987: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1986: ¥400,000 (Direct Cost: ¥400,000)
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| Keywords | Skyrme model / Nonlinear sigma model / Chiral soliton / Nuclear force / πN相互作用 / スカーミオン |
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| Research Abstract |
The nonlinear <sigma> model is considered to be a low-energy effective theory of the QCD. In the skyrme model the topological soliton of the nonlinear <sigma> model is identified with the baryon. To elucidate the accuracy of the model we investigated the nuclear force and the <pai>N interaction.
To extract the nuclear force from the model we proposed a method to quantize the spin and isospin degree of freedom in a systematical way suitable for a two-baryon system. Then, we clarified the characteristics of the NN, N<DELTA> and <DELTA><DELTA> interactions predicted by a generalized Skyrme model with higher derivative terms. The long-range part of the interaction was found to be given by the one-<pai>- and <rho>-exchange potentials with the correct magnitudes. It was also found that the short-range repulsion of the central part derived from the <omega>-meson coupling term is strong and has negative G-parity. However, the symmetric quartic term as the <sigma>-meson coupling term cannot describe the intermediate-range attraction necessary for the nuclear binding. Further, we derived the spin-orbit interaction of the Skyrme model. The resulting interaction has the <rho>-like exchange part with the correct sign and magnitude, but the <sigma>-like exchange part with the wrong sign. This remains as the crucial point of the model.
We described the pion-nucleon system by the quantum fluctuation around the Skyrmion. We found that there exist the zero modes originated from the translational and rotational invariance. We quantized the system by considering these zero modes correctly. Then, it was found that the <pai>N<delta> Yukawa coupling term can be obtained with the correct order of the magnitude. This term gives a finite width for the <delta> isobar state. Before this investigation the missing of such a term was considered to be serious for the modele.
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