Studies on Parity Non-conservation in Atomic Microwave Transitions

原子微波跃迁中宇称不守恒的研究

基本信息

批准号：
07804024
负责人：
NAKAYAMA Shigeru
金额：
$ 1.34万
依托单位：
Kagoshima University (1997)Hyogo University of Teacher Education (1995-1996)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1997
项目状态：
已结题

项目摘要

It is clear that laser experiments on atoms can provide important information on one of the most crucial questions of elementary particle physics, i.e., the validity of combining weak interactions and electro-magnetic interactions. The Weinberg-Salam theory (Standard Model) predicts the existence of additional weak interactions between the particles, electrons, protons and neutrons which from an atom. The weak interaction violates parity while the Electro-magnetic interaction conserves it. Therefore, it is possible to set up an experiment to search a very tiny explicitly parity violating effect in the presence of a very much larger than parity conserving backgrounds. The effect of weak neutral currents between electrons and the atomic nucleus could be detected in atoms with large atomic numbers, Z,since the effect was found to be roughly proportional to Z^3.We measured parity nonconserving (PNC) optical rotation on the optical transition in atomic thalium and lead. The result is consistent with current calculations based on the standard model. Moreover, limits have been set on the much smaller nuclear spin-bependent rotation amplitude. This is also consistent with theoretical estimates which include a nuclear anapole moment contribution.We are now investigating parity nonconservation effect on the microwave transition in hyperfine structures of Rb atom. Furthermore, the experimental results, when combined with the relevant atomic calculations, lead to a value for the mass of the Zo boson or, alternatively, place a limit on physics beyond the standard model through the isospin-conserving parameter, S.

显然，原子激光实验可以为基本粒子物理学最关键的问题之一提供重要信息，即弱相互作用和电磁相互作用相结合的有效性。温伯格-萨拉姆理论（标准模型）预测原子中的粒子、电子、质子和中子之间存在额外的弱相互作用。弱相互作用违反宇称性，而电磁相互作用则守恒宇称性。因此，可以建立一个实验，在存在比宇称守恒背景大得多的情况下，搜索非常微小的显式宇称破坏效应。电子和原子核之间的弱中性电流效应可以在具有大原子序数 Z 的原子中检测到，因为发现该效应大致与 Z^3 成正比。我们测量了光学上的宇称不守恒 (PNC) 旋光度。原子铊和铅的跃迁。结果与当前基于标准模型的计算结果一致。此外，还对更小的核自旋相关旋转幅度设定了限制。这也与包括核折点矩贡献在内的理论估计相一致。我们现在正在研究宇称非守恒效应对 Rb 原子超精细结构中微波跃迁的影响。此外，实验结果与相关原子计算相结合，得出 Zo 玻色子的质量值，或者通过同位旋守恒参数 S 对标准模型之外的物理施加限制。