| Project/Area Number |
11640271
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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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 | Nagoya University |
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Principal Investigator |
SAITO Sakae Nagoya University, Department of Physics, Professor, 大学院・理学研究科, 教授 (40022694)
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| Co-Investigator(Kenkyū-buntansha) |
ASAKAWA Masauki Nagoya University, Department of Physics, Associate Professor, 大学院・理学研究科, 助手 (50283453)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 2000: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1999: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Keywords | hadron / quark condensate / quantum chromodynamics / spectral function / フォーク対凝縮 / クォーク対凝縮 |
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| Research Abstract |
We have carried out research on the change of hadron properties in static electromagnetic field and have obtained the following results.
1. We have studied the spin-dependent polarizabilities of the nucleon with large N_c expansion. It has been known that in heavy baryon chiral perturbation theory (HBChPT) the next-to-leading order (NLO) contributions to the spin-dependent polarizabilities of the nucleon is very large and doubts have been casted on the effectiveness of HBChPT in the problem. We have shown that, to the contrary, the terms that give large contribution in NLO in HBChPT and that appear only in the next-to-next-leading order in HBChPT, are naturally taken into account in the leading order in large N_c expansion.
2. We have formulated a method to obtain the electromagnetic polarizabilities of baryons from the first principle of quantum chromodynamics by calculating the changes of quark condensates and baryon masses in electromagnetic field on lattice. When a constant magnetic field is applied, its strength is quantized due to the periodic boundary condition on lattice, and as a result weak magnetic fields cannot be applied. In order to circumvent this problem, it is necessary to change the strength of the magnetic field near the edges of the lattice. We have carried out preliminary calculations for large scale calculations with this method.
3. We have formulated a method to obtain spectral functions that are real-time quantities and related directly to physical observables from lattice data obtained in imaginary-time formalism, on the basis of Bayes' inference theory. Furthermore, we have proved the uniqueness of the solution in the method and formulated the method for the error analysis. We have succeeded in obtained spectral functions in several meson and baryon channels from actual lattice data.
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