Search for a permanent electric dipole moment (EDM) of the 129Xe atom

本文对同位素129-Xe的时间反转破坏永久电偶极矩(EDM)的测量实验进行了改进，旨在将目前1，5E-27ECM(95%CL)的实验极限提高两个数量级以上。对EDM的测量已经排除了各种超越粒子物理标准模型的理论。这种电火花加工的最佳极限是在抗磁原子199汞上测量的，其值为7，4E-30ECM)。为了提高测量精度，基于两个核自旋的自由进动，进行了3He/129-Xe时钟比对实验。自旋进动是由鱿鱼传感器探测到的。决定性的改进将通过一个新的磁屏蔽室实现，它允许更长的自旋相干时间(~1天)和显著提高的信噪比。由于这两种气体占据相同的体积，因此消除了它们的Larmor频率差异中的磁场依赖(共磁法)，从而消除了与电场切换相关的许多系统误差，例如，泄漏电流。因此，人们只对非磁相互作用项敏感，这里的类型是：测量的频移与施加的电场强度和129-Xe的电偶极矩成正比。

In this proposal an upgrade of the experiment for the measurement of the time-reversal violating permanent electric dipole moment (EDM) of the isotope 129-Xe is presented, which aims to improve the present experimental limit of 1,5E-27 ecm (95% CL) by more than 2 orders of magnitude. Measurements of EDMs have already excluded a variety of theories that go beyond the Standard Model of particle physics. The best limit for such an EDM was measured on the diamagnetic atom 199Hg with a value of 7,4E-30 ecm). To become more precise in measurement accuracy, a 3-He/129-Xe clock comparison experiment is performed based on free precession of the two nuclear spins. The spin precession is detected by SQUID sensors. The decisive improvements will be achieved with a new magnetically shielded room which permits longer spin coherence times (~1 day) and a significantly improved signal-to-noise ratio. Since both gases occupy the same volume, the magnetic field dependence in the difference of their Larmor frequencies is eliminated (co-magnetometry) and thus many systematic errors, e.g., leakage currents, correlated with the switching of the electric field. Thus, one is only sensitive to non-magnetic interaction terms, here of the type: The measured frequency shift is proportional to the applied electrical filed strength and the electric dipole moment of 129-Xe.