Michael Tarbutt

In the Standard Model of particle of physics, the electron has a tiny permanent electric dipole moment (EDM). In most theories that extend the Standard Model, this EDM is predicted to be many orders of magnitude larger due to new CP-violating mechanisms. Thus, EDM measurements are searches for new CP-violating physics which is deeply connected to the puzzle of the matter-antimatter asymmetry of the Universe. The most precise measurements of the electron EDM all use molecules. The molecules are spin polarized, and the EDM determined by measuring the spin precession frequency in an applied electric field. The precession is due to the interaction of the EDM with an effective electric field which can be exceptionally large for heavy polar molecules. To reach high precision we need long spin precession times, which is only possible with neutral molecules if they are cooled to microkelvin temperatures. I will present our efforts to measure the electron EDM using laser-cooled YbF molecules, both in a beam and, in the future, trapped in an optical lattice.