| Project/Area Number |
08640356
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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 | TOKYO INSTITUTE OF TECHNOLOGY |
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Principal Investigator |
OKA Makoto Tokyo Institute of Technology, Professor, 大学院・理工学研究科, 教授 (60144606)
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| Project Period (FY) |
1996 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1998: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1997: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1996: ¥600,000 (Direct Cost: ¥600,000)
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| Keywords | strong interaction / QCD / chiral symmetry / meson / nucleon / Bethe-Salpeter equation / 軸性U(1)対称性 / アノーマリー / エータ中間子 / ベーテ・サルピータ方程式 / 核子共鳴状態 / ベ-テサルピーター方程式 / SU(3)対称性 / バドロン / 電磁崩壊 |
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| Research Abstract |
Chiral effective theories of QOD are applied to the hadron spectra and properties of hadrons at finite temperature and baryon density.
We constructed an extended NJL model including a U(1)A breaking six-quark interaction vertex and found that a strong axial U(1) breaking is preferred phenomenological both in the meson and baryon sectors We also applied the improved ladder approximation in the Bethe-Salpeter equation for QCD and analyzed the pseudoscalar meson spectrum. The renormalization procedure is carried out for finite quark mass and an effective axialvector current is introduced so that the axial Ward-Takahashi identity is satisfied. Numerical calculation shows that the masses and decay constants of mesons are reproduced fairly well and the Gell-Mann-Oaks-Renner relation is satisfied for finite quark mass up to a hundred MeV.
W also applied the QCD sum rule to the positive and negative parity baryons and showed explicitly that their mass difference comes from the chiral symmetry breaking. Two distinct assignments of chiral symmetry is shown to exhibit different behaviors of hadrons.
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