Estimated performance of the TRIUMF ultracold neutron source and electric dipole moment apparatus

Abstract: Searches for the permanent electric dipole moment of the neutron (nEDM) provide strong constraints on theories beyond the Standard Model of particle physics. The TUCAN collaboration is constructing a source for ultracold neutrons (UCN) and an apparatus to search for the nEDM at TRIUMF, Vancouver, Canada. In this work, we estimate that the spallation-driven UCN source based on a superfluid helium converter will provide $(1.38\pm0.02) \times 10^7$ polarized UCN at a density of $217\pm3$~UCN/cm$^3$ to a room-temperature EDM experiment per fill. With $(1.51\pm0.02) \times 10^6$ neutrons detected after the Ramsey cycle, the statistical sensitivity for an nEDM search per storage cycle will be $(1.94\pm0.06) \times 10^{-25}\,e$cm (1$\sigma$). The goal sensitivity of $10^{-27}\,e$cm (1$\sigma$) can be reached within $280\pm16$ measurement days.