Design and construction of an apparatus for the experimental search for the electric dipole moment (EDM) of 129xe

我们建议测量同位素129Xe的永久电偶极矩（EDM），这意味着宇称P和时间反转对称性T的破坏，并且通过CPT定理，CP的破坏，电荷共轭C和宇称P的组合对称性。我们的目标是将目前的实验极限（dXe < 3x10-27 e cm）提高大约四个数量级。从历史上看，没有观测到粒子和原子的edm已经排除了比粒子物理学中任何其他单一实验方法更多的推测模型（超出标准模型）。在抗磁性原子199Hg （dHg < 3.1x10-29 ecm）中测得最精确的电火花加工极限。为了获得更严格的限制，我们提出了一个3He/129Xe时钟对比实验，用SQUID作为磁通量检测器检测气态、核极化3He或129Xe样品的自由自旋进动。同位3He/129Xe核自旋的进动可以作为Δν ~ dXeE型非磁自旋相互作用的超灵敏探针，因为磁偶极子相互作用（zeeman项）在它们的Larmor频率的频率差Δν中消失了。与自旋脉泽相比，自旋相干时间为tbbbb1天的自由自旋进动探测不存在维持相干自旋进动所必需的反馈环的系统限制。

We propose to measure the permanent electric dipole moment (EDM) of the isotope 129Xe, which would imply a breakdown of both parity P and time-reversal symmetry T and, through the CPT theorem, a breakdown in CP, the combined symmetries of charge conjugation C and parity P. Our goal is to improve the present experimental limit (dXe < 3x10-27 e cm) by about four orders of magnitude. Historically, the non-observation of EDMs of particles and atoms has ruled out more speculative models (beyond the Standard Model) than any other single experimental approach in particle physics. The most precise EDM limit was measured in the diamagnetic atom 199Hg (dHg < 3.1x10-29 e cm). To get more stringent limits, we propose a 3He/129Xe clock comparison experiment with the detection of free spin precession of gaseous, nuclear polarized 3He or 129Xe samples with a SQUID as magnetic flux detector. The precession of co-located 3He/129Xe nuclear spins can be used as ultra-sensitive probe for non-magnetic spin interactions of type Δν ~ dXeE, since the magnetic dipole interaction (Zeeman-term) drops out in the frequency difference Δν of their Larmor frequencies. Compared to spin masers, the detection of free spin precession with spin coherence times T > 1 day doesn’t have the systematic limitations of a feedback loop necessary to sustain coherent spin precession.