Search for the electric dipole moment of the electron with thorium monoxide

Understand

The electric dipole moment of the electron (eEDM) is a signature of CP-violating physics beyond the Standard Model.

• We describe an ongoing experiment to measure or set improved limits to the eEDM, using a cold beam of thorium monoxide (ThO) molecules.
• The metastable $H {}^3\Delta_1$ state in ThO has important advantages for such an experiment.
• We argue that the statistical uncertainty of an eEDM measurement could be improved by as much as 3 orders of magnitude compared to the current experimental limit, in a first-generation apparatus using a cold ThO beam.