Grant: Subatomic Physics Envelope - Research Tools and Instruments

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.