Sensitive Search for an EDM on the Electron using BaF Molecules

The observation of an electron electric dipole moment (eEDM) larger than the value allowed by the Standard Model (SM) of particle physics would be direct evidence of new physics. An upper limit of the eEDM constrains extensions to the SM. The barium monofluoride molecule (BaF) is an excellent system for electron EDM searches. Its structure gives rise to a large effective electric field Eeff→ experienced by the valence electron, if the molecules are polarized by an external electric field. The particular structure of BaF enables their slowing down in a Stark decelerator [1] to velocities of several 10 m/s. With the addition of laser cooling a bright and slow molecular beam can be created.
The components of the experiment, from the cryogenic source of BaF to the magnetically shielded interaction zone will be discussed and the experimental strategy will be explained. The goal of the project is a statistical limit of 5 · 10−30 e cm. At the projected precision the results of this experiment complement results in high energy physics experiments, e.g. at LHC.

[1] J.E. van den Berg, et al., J. Mol. Spec. 300, 22 (2014)