Towards a More Sensitive Measurement of the Atomic Electric Dipole Moment of Radium-225*

Permanent atomic electric dipole moments (EDMs) violate parity (P) and time reversal (T), and, assuming CPT symmetry, combined charge-conjugation and parity transformation (CP). Observable EDMs are enhanced in large-Z atoms with octupole-deformed, or pear-shaped, nuclei. Radium-225 has a significantly larger octupole deformation than nuclei used in other EDM experiments. In the Ra EDM experiment, radium atoms are vaporized, slowed, trapped, and transported to a science chamber between two high voltage electrodes. The first measurements of the upper limit of the EDM of Radium-225 were carried out in 2014 and 2015. For the second generation of measurements (2019—2020), upgrades to the atom detection method and applied electric field magnitude will improve our measurement sensitivity by up to two orders of magnitude. Additionally, we validated plans for a better longitudinal atom slower by experimentally verifying critical theorized branching ratios. The new slower is expected to provide an order of magnitude improvement in measurement sensitivity.