Search for the Electron EDM using Cs and Rb in Optical Lattice Traps

将进行一项实验，利用冷铯和铷原子寻找电子的电偶极矩。 将根据过去三年的经验教训对仪器进行适当修改，然后开始EDM数据收集。该实验使用原子发射和加载到一对平行的一维远离共振光学晶格陷阱在空间的磁屏蔽区域，激光冷却和光泵。EDM将通过观察相干原子在两个陷阱中方向相反的电场中的演化来测量。 预计该实验将对小至3x 10 -30 e-cm的EDM敏感，这比目前的限制提高了300倍。具有永久EDM的粒子意味着时间反演不变性和宇称不变性都被破坏。这两种对称性实际上在物理学的标准模型中都被违反了，标准模型预测基本粒子的EDM非常小，但非零。对标准模型提出的扩展倾向于预测更大的EDM，接近目前的实验上限。继续不观察电子数据模型将排除标准模型的许多可能扩展。相反，如果EDM被观察到，它将是第一个不能被纳入标准物理模型的实验结果。 如果在原子或分子中发现EDM，那么在本实验中使用的碱金属原子中提取基本物理学将比在其他更复杂的原子或分子中更可靠。这个实验解决了一个对基本粒子物理学至关重要的问题。这些问题通常通过高能实验来解决，但在这种情况下，原子物理学的精确工具可以应用于低得多的能量系统，同时成本也更低。本科生和研究生将接受实验研究方法的培训，并培养他们为国家科学工作者做好准备的技能。

An experiment will be pursued to search for the electric dipole moment (EDM) of the electron using cold cesium and rubidium atoms. The apparatus will be appropriately modified based on what has been learned over the last three years, and then EDM data collection will commence. The experiment uses atoms launched and loaded into a pair of parallel one-dimensional far-off-resonant optical lattice traps in a magnetically shielded region of space, laser-cooled and optically pumped. EDMs will be measured by observing coherent atom evolution in electric fields that are directed oppositely in the two traps. It is projected that the experiment will be sensitive to an EDM as small as 3x10-30 e-cm, which is a 300-fold improvement over the current limit. A particle with a permanent EDM implies that both time-reversal invariance and parity invariance are violated. Both of these symmetries are in fact violated in the standard model of physics, which predicts very small, but non-zero EDMs for fundamental particles. Proposed extensions to the standard model tend to predict much larger EDMs, close to the current experimental upper limit. Continued non-observation of EDMs would rule out many possible extensions to the standard model. Conversely, should an EDM be observed, it would be the first experimental result of any kind that cannot be incorporated into the standard model of physics. If an EDM is found in an atom or molecule, the extraction of the fundamental physics will be far more reliable in the alkali atoms used in this experiment than in other more complicated atoms or molecules. This experiment addresses a question of fundamental importance to elementary particle physics. Such questions are normally addressed with high energy experiments, but in this case the precision tools of atomic physics can be applied to a much lower energy system, with a concomitant lower cost. Undergraduates and graduate students will be trained in the experimental research methods and develop skills preparing them for the nation's scientific work force.