Argon Crystals for the Electron Electric Dipole Moment (eEDM) Search with the EDM^3 Collaboration

通过 EDM^3 协作进行电子电偶极矩 (eEDM) 搜索的氩晶体

• 批准号: RGPIN-2022-04603
• 负责人: Storry, Cody
• 金额: $ 1.75万
• 依托单位: York University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=763109
• 关键词: Argon; Crystals; Electron; Electric; Dipole

The proposed research is toward the search for the permanent electron (e-) electric dipole moment (EDM). The e- is a point particle in the classical physics picture but physics predicts an asymmetry in the charge near it. Detecting the precession or wobble of the eEDM in an electric field, in polar molecules for example, will confirm the expected, yet elusive, eEDM. To probe for this effect, many e- (improved statistics) observed for long periods (characterized by precession time) are required. Measurements by the ACME II collaboration indicate an eEDM below 1.1*10^--29 e-cm. The challenge is that the physical size of the e EDM is tiny and its measurement will require development of new techniques. The projected sensitivity of our recently established EDM^3 (Electric Dipole Measurements using Molecules within a Matrix) collaboration will find the eEDM or limit it at a level of <10^-34 ecm, a 10^5 times improvement. My independent research contribution to the EDM^3 will provide the ideal substrate for Argon (Ar) crystal growth in which the polar molecules are fixed. Specifically, the short-term objectives of this Discovery application are to: (1) produce highly pure cryogenic Ar solids from liquified Ar in a crystal form; (2) make crystallographic measurements to confirm it is a monolithic crystal with the required low defect and impurity content; and (3) manipulate this cryogenic crystal transporting it into separate apparatus where the polar molecules are deposited during additional crystal growth on this idea substrate for EDM^3 goals. These objectives are toward EDM^3 goals where an apparatus is under development to observe the first polar molecules frozen in an Ar solid. Here argon is frozen on a sapphire substrate and freezes in an unknown, random orientation due to the sapphire surface potentials. A cylindrical, cm diameter, flawless, Ar crystal with embedded polar molecules is to be needed for EDM^3 objectives. Finding an asymmetry in the charge near the e would lead to a permanent eEDM, the discovery of which would be ground-breaking, narrowing the range of possible physics models describing the universe, and providing evidence of new particles or interactions that lead to the observed matter--antimatter asymmetry in the universe. Our new approach will increase the e number observed and the duration of time they are observed by fixing the molecules in a crystal of frozen Ar. Our small laboratory apparatus is novel: measurements that detect this tiny size probe energy scales beyond the reach of high energy accelerators, making our research competitive with LHC experiments at CERN but at a tiny fraction of the cost and housed at a Canadian University. This project will enable 10 undergraduates and 7 graduates to receive training in high tech fields ideal for careers in today's industries. The success of our research will cement the way to achieve the most sensitive measurement yet of the eEDM.

拟议的研究旨在寻找永久电子（e-）电偶极矩（EDM）。 e-是经典物理图中的点粒子，但物理学预测它附近的电荷存在不对称性。检测 eEDM 在电场中（例如极性分子中）的进动或摆动，将证实预期但难以捉摸的 eEDM。为了探究这种效应，需要长期观察（以进动时间为特征）的许多电子（改进的统计数据）。 ACME II 协作的测量表明 eEDM 低于 1.1*10^--29 e-cm。挑战在于 e EDM 的物理尺寸很小，其测量需要开发新技术。 我们最近建立的 EDM^3（使用矩阵内分子的电偶极子测量）协作的预计灵敏度将发现 eEDM 或将其限制在 <10^-34 ecm 的水平，即提高 10^5 倍。我对 EDM^3 的独立研究贡献将为固定极性分子的氩 (Ar) 晶体生长提供理想的基底。具体来说，该发现应用的短期目标是：（1）从液态Ar以晶体形式生产高纯低温Ar固体； (2)进行晶体学测量，确认其为具有要求的低缺陷和杂质含量的单片晶体； (3) 操纵这种低温晶体，将其运输到单独的设备中，在该设备上进行额外的晶体生长过程中，极性分子会沉积在该理想基板上，以实现 EDM^3 目标。这些目标是针对 EDM^3 目标，其中正在开发一种设备来观察冷冻在 Ar 固体中的第一个极性分子。此处，氩气被冻结在蓝宝石基板上，并由于蓝宝石表面电势而以未知的随机方向冻结。 EDM^3 物镜需要具有厘米直径、无瑕疵、嵌入极性分子的圆柱形 Ar 晶体。 发现 e 附近电荷的不对称性将导致永久的 eEDM，其发现将具有开创性，缩小描述宇宙的可能物理模型的范围，并提供导致观察到的新粒子或相互作用的证据宇宙中物质-反物质的不对称性。我们的新方法将通过将分子固定在冷冻氩晶体中来增加观察到的 e 数和观察持续时间。我们的小型实验室设备很新颖：检测这种微小尺寸探针能量的测量超出了高能加速器的范围，这使得我们的研究与欧洲核子研究中心的大型强子对撞机实验具有竞争力，但成本却只有加拿大大学的一小部分。该项目将使 10 名本科生和 7 名研究生能够接受适合当今行业职业的高科技领域的培训。我们研究的成功将巩固实现 eEDM 迄今为止最灵敏测量的方法。