Study of a few-nucleon system using electron scattering (relativistic effects, meson exchange effects, contributions of quarks)

1.完成了东北大学的^&lt；40&gt；Ca(e，e‘p)实验研究，并与已有的^&lt；12&gt；C和^&lt；16&gt；0的实验结果进行了比较。实验得到的截面几乎是用相对论DWIA计算得到的理论截面的一半。这一结果表明，计算中遗漏了一些重要因素。介子交换电流对~(12)C的贡献最大，对于较重的核则变小。在MIT-Bates四动量转移q^2=0.33(GeV/c)^2的虚光子康普顿散射实验中得到的质子的极化率与用低能展开和色散关系分析的结果有很大的不同。这种差异在更高的动量转移中看不到。在MIT-BATES和JLab用色散理论得到的偶极参数是一致的，但与…有很大不同在美因茨获得的价值更高。我们已经分析了JLab的^3He(e，e‘p)实验数据，并在《物理评论快报》上发表了结果。在1GeV/c附近，我们用不同的波函数对质子在~3He中的动量分布进行了比较，发现没有一种计算结果与实验结果相一致，这表明描述原子核需要超越核子的自由度。我们制作了兰姆移位式偏振仪，并对其性能进行了测试。用旋光仪直接测量了氢核的三个磁子能级的比例。我们在京都大学利用电子储存环中的自限制离子靶进行了电子散射的实验。该靶标利用电子束诱导的静电场捕获正原子离子。利用分析系统监测被捕获离子的状态，观察被提取离子的电荷态分布。我们已经确认Cs离子实际上被困在了目标中。我们还对安装在靶区的线状目标的散射电子探测系统的性能进行了评估。较少

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