Ultrahigh-Sensitivity Search for an Electric Dipole Moment of^<129>Xe atom by Means of Nuclear Spin Maser with Artificial Feedback

利用人工反馈核自旋微波激射器超高灵敏度搜索^<129>Xe原子的电偶极矩

基本信息

批准号：
15104003
负责人：
ASAHI Koichiro
金额：
$ 63.23万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (S)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2007
项目状态：
已结题

项目摘要

Violation of CP invariance, known for more than 40 years in neutral K decay and recently confirmed also in B decay, remains one of vital subjects in contemporary particle physics. The standard Model (SM) includes the CP violation in a form of complex phase in the K-M matrix elements and well represents the observed flavor-changing K and B decays, but never provide a permanent electric dipole moment (EDM) of detectable size. On the other hand, models proposed beyond the SM, such as supersymmetric one, predict sizeable values for EDM, thus rendering EDM an exclusive position as a probe of physics beyond the SM. The present research has aimed at development of new scheme of nuclear spin maser that enables precision determination of spin precession frequency, in order to pave a route for ultrahigh-sensitivity search for an EDM in a ^<129>Xe atom.^<129>Xe nuclear spins of Xe gas contained in a 22 mm-diameter glass cell were successfully polarized by spin exchange with optically pumped Rb vapor, their precession was detected by probe Laser light, and a self-sustaining precession by means of an artificial feedback was observed for the first time. The observed precision in frequency proved to improve as Δv ∝ 1/T^<1.5> as a function of the measurement time T until T = 3000 s, and then tended to be flattened. Following this result, we worked out several improvements in the setup, including the magnetic shielding, magnet current stabilization, Laser operation and wavelength stabilization, and cell temperature control, and finally attained Δv = 9.3 nHz (amounting to EDM sensitivity of Δd 〜 9×10^<-28> ecm) in a measurement time T = 30000 s. Also, a number of issues were identified that have decisive effects on the v precision and definitely deserve further work for improvement. We thus conclude that the present work has confirmed effectiveness of novel method for the atomic EDM search, and has clarified the directions that should enable the long awaited EDM precision.

CP 不变性的破坏在中性 K 衰变中已为人所知 40 多年，最近在 B 衰变中也得到了证实，它仍然是当代粒子物理学的重要课题之一。标准模型 (SM) 包括以复相形式存在的 CP 破坏。 K-M 矩阵元素并很好地代表了观察到的风味变化 K 和 B 衰减，但从未提供可检测大小的永久电偶极矩 (EDM)。另一方面，在 SM 之外提出的模型（例如超对称模型）可以预测相当大的值。价值观从而使 EDM 成为超越 SM 的物理学探针，目前的研究旨在开发新的核自旋微波激射器方案，能够精确确定自旋进动频率，从而为超高速核自旋脉泽铺平道路。对 ^<129>Xe 原子中的 EDM 进行灵敏度搜索。^<129>Xe 包含在 22 mm 直径玻璃池中的 Xe 气体的核自旋通过光学自旋交换成功地极化泵浦铷蒸气，它们的进动被探测激光检测到，并且首次观察到通过人工反馈的自持进动，频率的观测精度被证明提高为Δv∝1/T^<1.5>。作为测量时间 T 的函数，直到 T = 3000 s，然后趋于平坦。根据这个结果，我们对设置进行了一些改进，包括磁屏蔽、磁体电流。稳定性、激光操作和波长稳定性以及池温度控制，最终在测量时间 T = 30000 s 内达到 Δv = 9.3 nHz（相当于 Δd 〜 9×10^<-28> ecm 的 EDM 灵敏度）。我们发现了许多对 v 精度有决定性影响的问题，并且绝对值得进一步改进，因此我们得出的结论是，目前的工作已经证实了原子 EDM 新颖方法的有效性。搜索，并明确了实现期待已久的 EDM 精度的方向。