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)在粒子物理的新标准模型(SM)的发展中起着至关重要的作用。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。尽管取得了巨大的实验成就，如夸克和希格斯玻色子的存在，但它未能解释一些大问题，如：什么是暗物质？为什么宇宙中的物质比反物质多？这些问题推动了对标准模型的扩展，该模型预测了新粒子和/或新自然力的存在。其中许多理论扩展自然地预测了粒子或原子的有限永久EDM的存在，其大小比当前SM所允许的大许多个数量级。如果被发现，它将被誉为新物理学的源头，并为粒子物理的“新”标准模型提供亟需的指导。 对中子、电子和汞-199原子的电火花加工设定了最精确和最重要的限制，导致了严格的约束或推翻了SM的许多理论扩展。我们的目标是改进对中子电偶极矩的限制(或找到一个有限的)。通过与日本的国际合作，我们正在加拿大国家核物理和粒子物理实验室TRIUMF建造下一代超冷中子(UCN)源。利用这个源的旗舰实验将搜索中子电偶极矩。TRIUMF UCN源将基于超流体He-II，它不会像以前的源一样受到UCN生产的限制，并建立在日本15年发展计划的基础上。实验将分两个阶段进行：第一阶段包括安装和运行在日本制造的UCN源和nEDM样机，并转移到TRIUMF；第二阶段包括升级的UCN源和nEDM实验，旨在将目前nEDM的最佳测量提高30倍。 这项赠款申请侧重于在TRIUMF完全集成第一阶段nEDM设备和来自日本的UCN源所需的基本设备。来自日本的许多部件将被重复使用，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。中子电火花加工实验的另一个关键方面是控制与磁场有关的系统效应，为了解决这一问题，我们正在为第一阶段开发一台Hg-199磁强计。这台仪器是由不列颠哥伦比亚大学的同事领导的，这里需要的设备和材料将使这一系统快速发展。