Study of a few-nucleon system using electron scattering (relativistic effects, meson exchange effects, contributions of quarks)
| Project/Area Number |
17540229
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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 |
Particle/Nuclear/Cosmic ray/Astro physics
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| Research Institution | Tohoku University |
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Principal Investigator |
TAMAE Tadaaki Tohoku University, Graduate School of Science, Associate Professor, 大学院理学研究科, 助教授 (10124174)
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| Project Period (FY) |
2005 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2006: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 2005: ¥2,200,000 (Direct Cost: ¥2,200,000)
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| Keywords | (e, e'p) experiment / relativistic theory / meson exchange current / virtual-photon Compton scattering / polarizability of proton / ^3He(e, e'p) experimen / Lamb-shift polarimeter / self-confining radioactive io target / 仮想コンプトン散乱 / 低エネルギー展開 / 分散関係式 / 内部標的電子散乱 / イオントラップ / ワイヤーターゲット / (e,e'p)反応 / 相対論的歪曲波衝撃近似 / ラムシフト型偏極度計 / 内部標的電子散乱実験 / 偏極重陽子標的 |
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| Research Abstract |
1. We have completed the study of ^<40>Ca(e, e'p) experiment made at Tohoku University, and compared it with previously studied results of ^<12>C and ^<16>0. The experimentally-obtained cross sections were almost half of theoretically obtained ones using relativistic DWIA calculations for all targets. This result suggests that some important ingredients are missing in the calculation. The contribution of the meson exchange currents is largest for 12C, and becomes smaller for heavier nuclei.
2. Polarizabilities of the proton obtained from an experiment of virtual-photon Compton scattering made at a four-momentum transfer of Q^2 = 0.33 (GeV/c)^2 at MIT-Bates are much different from each other between the values that were analyzed using the low energy expansion and using dispersion relation. Such a discrepancy is not seen at higher momentum-transfers. The dipole parameters obtained at MIT-Bates and at JLab using the dispersion theory are consistent each other, but different very much from
… More
the value obtained at Mainz.
3. We have analyzed data of the ^3He(e, e'p) experiment made at JLab, and published the result on Physical Review Letters. We compared the momentum distribution of protons in ^3He with calculations using various wave functions, and found no calculations agree with the experimental result near 1 GeV/c. It suggests that degrees of freedom beyond nucleons are needed for description of nuclei.
4. We have fabricated a Lamb-shift type polarimeter and tested its performance. The fraction of three magnetic sub-levels of the deuteron was directly measured using the polarimeter.
5. We have performed test experiments of electron scattering using a self-confining ion target in an electron storage ring at Kyoto University. This target traps positive atomic ions using electrostatic field induced by an electron beam. The condition of trapped ions was monitored by an analyzer system, which observed charge-state distribution of extracted ions. We have confirmed Cs ions were actually trapped in the target. We also evaluated the performance of the scattered-electron detection system using wire targets installed in the target region. Less
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Report
(3 results)
Research Products
(14 results)
