1999 Fiscal Year Final Research Report Summary
QCD Corrections and Clues to New Physics in Precision Experiments
| Project/Area Number |
09640364
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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 | Hiroshima University |
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Principal Investigator |
KODAIRA Jiro Hiroshima University, Department of Physics, Associate Professor, 理学部, 助教授 (40127080)
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| Co-Investigator(Kenkyū-buntansha) |
ONOGI Tetsuya Hiroshima University, Department of Physics, Research Associate, 理学部, 助手 (70211802)
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| Project Period (FY) |
1997 – 1999
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| Keywords | QCD / Radiative Corrections / Perturbation / Lattice QCD / Precision Experiment |
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| Research Abstract |
The aim of this project, is to investigate the QCD effects in various processes. To find a clue to New Physics beyond the Standard Model (SM), the reduction of the theoretical ambiguities coming from QPD is essential.
1. For both high and low energy processes, the power corrections are very important, to make a precise prediction of SM. We investigated the higher twist, operator which is one of the sources of power corrections. We have shown how to calculate the anomalous dimensions in a manifestly covariant, approach and demonstrated the explicit, evaluation for the case of twist-3 operators.
2. The behavior of structure functions at small Broken x receives a lot of interests recently. We have studied the gィイD21ィエD2 polarized structure function at small x. Our numerical results showed that the leading logarithmic approximation would be quite unstable against, higher order corrections.
3. The heavy particles like the top-quark are expected to have important information on the symmetry breakdown in SM. We have investigated the QCD corrections to the spin correlation in the top-quark productions in arbitrary spin bases. What, we have found is that, the QCD correction is very small against the intuitive expectations. This result is very important, when one tries to find some clue to New Physics by measuring the spin correlations. We have also investigated the effects of anomalous couplings in the presence of QCD corrections. Now the paper is in preparation.
4. The heavy quark effective theory and/or the non-relativistic QCD is a powerful formulation from both analytical and numerical viewpoints. We have studied the B meson on the lattice using this formalism. We have succeeded to improve the theoretical predictions and these results are important to investigate the problems like the CP violation.
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