Study of Parity Non-conservation Phenomena in Rare-earth Atoms

本研究的目的是在广泛的同位素范围内测量靠近相反宇称能级的稀土原子对的宇称混合，并检验除电弱标准模型之外的各种理论模型。1995-1997财政年度取得的成果如下：对新型环形染料和钛/蓝宝石激光器的绝对波长进行了从可见光到红外区的校准。利用Rb-D2线的饱和吸收和调频光谱信号稳定激光器，使绝对频率漂移从几百MHz/h提高到0.7MHz/h。在大型真空室内新安装了原子束烘箱、静电电极和电磁铁，并制作了CAMAC接口模块和软件来控制电磁场方向和激光偏振。经综合测试，整个系统运行良好，稳定原子束持续时间提高到70小时。利用该系统，系统地测量了Sm、Pr和Tm原子的超精细结构、同位素位移和Zeeman-Stark效应，并获得了精确的光谱数据。特别是在smi水平上，观察到较大的Stark分裂，并且首次发现了张量极化率的明显同位素依赖性。上述成果在日本物理学会会议上发表了16篇口头报告，在国际会议上发表了4篇报告，在科学期刊上发表了8篇文章，在广岛大学理学院发表了5篇硕士论文和3篇博士论文。

The purpose of this study is to measure the parity mixing of close-lying opposite-parity level pairs of rare earth atoms over wide range of isotopes and to inspect various theoretical models beyond the electroweak standard model. The obtained results during 1995-1997 fiscal years are described in the following.1. The absolute wavelengths of the new ring dye and Ti/Sapphire lasers were calibrated from visible to infrared region. The laser was stabilized with the signal from saturated-absorption and frequency-modulated spectroscopies of Rb-D2 line, and the absolute frequency drift was improved from several hundred MHz/h to 0.7MHz/h.2. The atomic-beam oven, electrostatic electrodes and electromagnet were newly installed in large-size vauum chamber, and CAMAC interface module & software were prepared to control the directions of electromagnetic fields and laser polarization. As a result of general tests, the whole system was operated well and the duration time of stable atomic beam was improved to 70 hours.3. By using the above system, hyperfine structures, isotope shifts and Zeeman-Stark effects were systematically measured for many close-lying opposite-parity level pairs of Sm, Pr and Tm atoms, and precise spectroscopic data were obtained. Particularly in a level of Sm I,large Stark splitting was observed, and clear isotope dependence of the tensor polarizability was found for the first time.4. The above results were published in 16 oral presentaitons in the meetings of Japanese Physical Society, 4 presentations in international conferences, 8 articles in the scientific journals, 5 master and 3 doctoral theses in the Faculty of Science, Hiroshima university.