Abstract

In 1984, Sushkov et al.¹ pointed out that heavy, diatomic ²∑ or ²∏ molecules could be spectacularly sensitive systems in which to search for a permanent electric dipole moment (EDM) of the electron. In an external electric field $\overrightarrow{E}$, the molecule can have an electric dipole interaction of the form $\xi d_e\widehat{\sigma }\cdot \overrightarrow{E}$, where d_e is the electron EDM and $\widehat{\sigma }$ is a unit vector along the electron spin direction. The effective molecular EDM ξd_e is larger than that of the free electron by an enhancement factor ξ which can be very large. Since a variety of theories concerning elementary particle physics beyond the standard model predict the existence of a small electron EDM, such a search can provide useful constraints on particle theories and provide information that is complementary to super-high-energy accelerator experiments.

© 1994 IEEE