| Project/Area Number |
06640406
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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 | Saga University |
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Principal Investigator |
KUMANO Shunzo Saga University, Physics department, Associate Professor, 理工学部, 助教授 (10253577)
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| Co-Investigator(Kenkyū-buntansha) |
HASEGAWA Akira Saga University, Physics Department, Professor, 理工学部, 教授 (20039259)
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| Project Period (FY) |
1994 – 1996
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| Project Status |
Completed (Fiscal Year 1996)
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| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1996: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1995: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1994: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Keywords | structure function / nucleon / nucleus / parton / quark / gluon / Q^2 evolution / scaling violation |
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| Research Abstract |
1.Q^2 evolution equation We developed a computer program for solving the Altarelli-Parisi Q^2 evolution equations. First, a Laguerre-polynomial method is studied. We find that merely twenty polynomials are enough for obtaining accurate evolution results. Next, a brute-force method is investigated. In this method, the variables x and Q^2 are divided into small steps, then differentiation and integration are simply calculated. We find that 2000 x steps and 200 Q^2 steps are necessary for getting accurate results. We explicitly showed that higher-twist effects are important in the small Q^2 region in comparison with experimental data. The method was applied to the polarized structure function g_1.
2.Parton distributions in nuclei [(u-d)_A, F_<A(1)3>(x)] Considering parton recombination effects in a uncleus, we find that unclear interactions could create a finite u-d distribution even it vanishes in the nucleon. Therefore, we have to be careful in comparing unclear Drell-Yan data with the NMC data. Next, shadowing in the F_3 structure function is investigated by using two different descriptions : parton-recombination and aligned-jet models. We find that they give very different predictions at small x, so that they could be tested by future experiments.
3.Antiquark distribution u-d in the nucleon NMC finding of the Gottfried sum rule violation indicated the difference between u and d. Many papers are published on this topic. I wrote a summary paper and submitted it to Physics Reports.
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