1995 Fiscal Year Final Research Report Summary
Grand Unified Theories based on Dynamical Symmetry Breaking
| Project/Area Number |
06640387
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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 |
素粒子・核・宇宙線
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
KUGO Taichi Kyoto University, Graduate School of Science Professor, 大学院理学研究科, 教授 (00115833)
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| Project Period (FY) |
1994 – 1995
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| Keywords | Nambu-Jona-Lasinio model / gauge-Higgs-Yukawa system / nontriviality / renormalizability / background field method / non-Abelian gauge theory / color confinement |
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| Research Abstract |
The research results of our project for two academic years in 1994-1995 are as follows :
1. A new lagrangian way of defining the Nambu-Jona-Lasinio (NJL) model is proposed, which possesses an intrinsic ultraviolet cutoff by the higher derivative fermion kinetic term and maintains all the external gauge invariances. There we also discussed the quantization method of such a higher-derivative system, current operators and chiral anomaly problems.
2. Based on the renormalization group method, the gauge-Higgs-Yukawa system was analyzed whether it is nontrivial or not ; namely, whether it can give a well-defined interacting theory when the ultraviolet cutoff goes to infinity. We proved that it is nontrivial under the following conditions : i) there exists an asymptotically free gauge interaction, whose approach to the asymptotic freedom should not be so rapid, ii) the Yukawa coupling should be smaller than or equal to an upperbound, and iii) the scalar quartic coupling is not an independent parameter but is uniquely determined by the Yukawa and gauge coupling constants. Based on the result, the gauged NJL model is proved to be renormalizable in four dimensions.
3. The procedure was clarified how one can obtain the physical S-matrix from the gauge-invariant effective action in the background field (BF) method. We gave a precise proof that it gives the same S-matrix as the one obtained by the usual non-gauge-invariant (BRS invariant) effective action.
4. We found a new relation 1+u=Z_1/Z_3=Z_<vertex>/Z_<wave-function>, where the left-hand side is the quantuty that 1+u = 0 is known to give a sufficient condition for the color confinement to occur, and the righthand side stands for the ratio of the renormalization factors, Z_<vertex>/Z_<wave-function>, which is universal (i.e., matter-independent),
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Research Products
(12 results)
