Phase 1 nEDM experiment support

第 1 阶段 nEDM 实验支持

• 批准号: SAPEQ-2017-00009
• 负责人: Mammei, Russell
• 金额: $ 3.4万
• 依托单位: University of Winnipeg
• 依托单位国家: 加拿大
• 项目类别: Subatomic Physics Envelope - Research Tools and Instruments
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=616794
• 关键词: Phase; nEDM; experiment; support

The search for permanent electric dipole moments (EDM) in particles or atoms plays a critical role in the development of the "new" Standard Model (SM) of particle physics. The current SM of particle physics is the theory that classifies all the known subatomic particles and their interactions. Despite huge experimental success, such as existence of the quarks and the Higgs Boson, it fails at explaining some big questions such as: What is Dark Matter? and Why is there more matter than antimatter in the universe? These questions have motivated the search for extensions to the Standard Model, which predict the existence of new particles and/or new forces of nature. Many of these theoretical extensions naturally predict the existence of a finite permanent EDM of a particle or atom many orders of magnitude larger than allowed by the current SM. If found, it would be heralded as a source of new physics and provide much needed guidance toward a "new" standard model of particle physics. The most precise and significant limits have been set on the EDM of the neutron, the electron, and the Hg-199 atom, leading to tight constraints or disproving many theoretical extensions of the SM. We aim to improve the limits on the (or find a finite) electric dipole moment of the neutron. Through our international collaboration with Japan, we are building a next generation ultracold neutron (UCN) source at TRIUMF, Canada's National Laboratory for Nuclear and Particle Physics. The flagship experiment utilizing this source will search for the neutron electric dipole moment. The TRIUMF UCN source will be based on superfluid He-II, which does not suffer the same UCN production limitations of previous sources and builds upon on a 15 year development program in Japan. The experiment will occur in two phases: Phase I involves the installation and running of a prototype UCN source and nEDM apparatus, built in Japan and moved to TRIUMF, while Phase II includes an upgraded UCN source and nEDM experiment aimed at improving the current best measurement of the nEDM by a factor of 30. This grant request focuses on essential equipment required to fully integrate the Phase I nEDM apparatus and UCN source, from Japan, at TRIUMF. Many components from Japan will be reused but due to the different experimental conditions at TRIUMF compared to that in Japan, we require more UCN guides, a new nEDM cell valve, and an external magnetic field compensation system. Another key aspect of neutron EDM experiments is the control of systematic effects related to magnetic fields and to address this for Phase I we are developing a Hg-199 comagnetometer. This instrument is being led by our University of British Columbia colleagues, where equipment and materials requested herein will allow the rapid progress of this system.

寻找粒子或原子中的永久电偶极矩 (EDM) 在粒子物理学“新”标准模型 (SM) 的发展中发挥着关键作用。当前粒子物理学的 SM 是对所有已知的亚原子粒子及其相互作用进行分类的理论。尽管实验取得了巨大成功，例如夸克和希格斯玻色子的存在，但它无法解释一些重大问题，例如：什么是暗物质？为什么宇宙中物质多于反物质？这些问题促使人们寻求标准模型的扩展，该模型预测新粒子和/或新自然力的存在。许多这些理论扩展自然地预测了粒子或原子的有限永久 EDM 的存在，该 EDM 比当前 SM 允许的数量级大许多数量级。如果被发现，它将被誉为新物理学的源泉，并为粒子物理学的“新”标准模型提供急需的指导。 对中子、电子和 Hg-199 原子的 EDM 设定了最精确和重要的限制，导致严格的约束或反驳了 SM 的许多理论扩展。我们的目标是改善（或找到有限）中子电偶极矩的限制。通过与日本的国际合作，我们正在加拿大核与粒子物理国家实验室 TRIUMF 建造下一代超冷中子 (UCN) 源。利用该源的旗舰实验将寻找中子电偶极矩。 TRIUMF UCN 源将基于超流体 He-II，它不会受到与以前源相同的 UCN 生产限制，并且建立在日本 15 年的开发计划之上。该实验将分两个阶段进行：第一阶段涉及安装和运行原型 UCN 源和 nEDM 设备，在日本制造并移至 TRIUMF，而第二阶段包括升级的 UCN 源和 nEDM 实验，旨在改进当前的最佳测量nEDM 的 30 倍。 该拨款请求重点关注完全集成来自日本 TRIUMF 的第一阶段 nEDM 设备和 UCN 源所需的基本设备。许多来自日本的组件将被重复使用，但由于 TRIUMF 的实验条件与日本不同，我们需要更多的 UCN 导轨、新的 nEDM 单元阀和外部磁场补偿系统。中子 EDM 实验的另一个关键方面是控制与磁场相关的系统效应，为了解决第一阶段的问题，我们正在开发 Hg-199 共磁计。该仪器由我们不列颠哥伦比亚大学的同事领导，此处要求的设备和材料将使该系统能够快速进展。