Radium Atoms, Time-Reversal, and Physics Beyond the Standard Model

Electric dipole moments (EDMs) are signatures of time-reversal, parity, and charge-parity (CP) violation, which makes them a sensitive probe of expected new physics beyond the Standard Model, such as supersymmetry. This is because new, undiscovered sources of CP-violation are needed to explain the existence of all matter in the universe. Due to its large nuclear octupole deformation and high atomic mass, the radioactive Ra-225 isotope is a favorable EDM case; it is particularly sensitive to CP-violating interactions in the nuclear medium. To measure this rare isotope, we have developed an approach to measuring EDMs by using lasers to cool those atoms to 40 micro-Kelvins, and trapping them in an optical dipole trap. Using this method, we have found the EDM of radium to be less than 1.4e-23 e-cm. Upcoming improvements are expected to dramatically improve our sensitivity, and significantly improve on the search for new physics in several sectors.