Ultracold Neutron Electric Dipole Moment Experiment

本实验旨在比以往更精确地测量中子电偶极矩（nEDM）。nEDM的新测量将对涉及标准模型之外的新电荷宇称（CP）违反源的理论施加更严格的限制。据信，为了解释当今宇宙中物质对反物质（重子不对称）的优势，这些都是必需的。一般来说，该实验将限制大量不保留CP的新物理场景。一项新的测量也可能影响标准模型中一个长期存在的谜题，包括明显缺乏由强作用力引起的CP违反。非零nEDM的发现将是一个重大发现，因为它将阐明一系列广泛的理论。******这项研究的一个关键工具是超冷中子（UCN）的新来源。UCN是缓慢移动的中子，可以储存在材料瓶、磁瓶和引力瓶中。一旦用这种方法对它们进行了限制，就可以非常仔细地研究它们的性质，以寻找与基于粒子物理学标准模型的预期的偏差。******我们的科学合作被命名为TUCAN （TRIUMF超冷先进中子）合作。在过去的三年里，在日本合作者的帮助下，我们在加拿大（位于不列颠哥伦比亚省温哥华的TRIUMF）完成了一个新的UCN来源。加拿大创新基金会和包括日本在内的合作伙伴提供了大量资金，用于升级UCN源和建设新的中子EDM实验。一旦升级完成，该源预计将提供世界上最高密度的UCN。该源将用于将基础物理实验推进到前所未有的精度水平。******我们在未来三年的活动将包括完成UCN源升级和nEDM实验建设。我们还将利用TRIUMF现有的UCN资源进行旨在回答实验总体成功的关键问题的实验。

Our experiment aims to measure the neutron electric dipole moment (nEDM) more precisely than ever before. A new measurement of the nEDM will place even tighter constraints on theories involving new sources of Charge-Parity (CP) violation beyond the standard model. It is believed these are required in order to explain the predominance of matter over antimatter (baryon asymmetry) in the universe today. Quite generically, the experiment will constrain broad classes of new physics scenarios which do not conserve CP. A new measurement also could impact a long-standing mystery in the standard model, involving the appararent lack of CP violation arising from the strong force. A discovery of a non-zero nEDM would be a major discovery, because it would shed light on a broad range of theories.******A key tool in this search is a new source of ultracold neutrons (UCN). UCN are slow moving neutrons that can be stored in material, magnetic, and gravitational bottles. Once they've been confined using such methods, their properties can be studied very carefully to search for deviations from expectations based on the standard model of particle physics.******Our scientific collaboration is named the TUCAN (TRIUMF Ultracold Advanced Neutron) collaboration. In the past three years, we have completed a new source of UCN in Canada (at TRIUMF, Vancouver, BC) with the help of collaborators from Japan. New funds for upgrades to the UCN source and for the construction of a new neutron EDM experiment have been secured from the Canada Foundation for Innovation and partner contributions including a substantial contribution from Japan. Once the upgrades are complete, the source is projected to provide the highest density of UCN in the world. The source will be used to advance fundamental physics experiments to unprecedented levels of precision.******Our activities over the next three years will involve the completion of the UCN source upgrade and the nEDM experiment construction. We will also use the existing UCN source at TRIUMF for experiments aimed at answering critical questions for the overall success of the experiment.