Measuring the electron's electric dipole moment in an ultracold beam of YbF molecules

The processes that produced more matter than antimatter in the early universe are not understood [1]. One precondition is the combined violation of charge conjugation and parity symmetries (CP-violation) beyond that found in the Standard Model. In almost all theories, CP-violation is also a prerequisite for the electron to have an electric dipole moment (EDM, d_e). Thus, a measurement of d_e tests theories beyond the Standard Model.

The value of d_e can be determined by measuring the precession rate of the electron spin in a strong electric field. Heavy polarized molecules with their high intra-molecular fields have already set a limit of |d_e| < 4.1×10⁻³⁰ e cm [2]. We aim to improve on this result by using a collimated, bright beam of laser cooled YbF molecules [3,4]. I report the first interferometer fringes and EDM data recorded on this experiment and present its key features, showing that d_e can be measured with a projected uncertainty of 5×10⁻³⁰ e cm per day.



[1] L. Canetti et al. New J. Phys. 14 095012 (2012)

[2] T. S. Roussy et al. Science 381, 46-50 (2023)

[3] N. J. Fitch, et al. Quantum Sci. Technol., 6, 014006, (2021)

[4] X. Alauze et al. Quantum Sci. Technol. 6, 044005 (2021)