Chemistry Department Seminar

The possibility of an electron electric dipole moment (EDM) is predicted by current theories of physics, including the Standard Model. Whereas the value predicted by the Standard Model (~10^-38 e cm) is beyond the reach of current experiment, most other theories, including Supersymmetry, predict a dipole moment close to that of the current limit (10^-27 e cm). Thus the search for an electron EDM is an important test of theories beyond the Standard Model. I show that PbF molecules cooled to 0.1 mK and confined by a spatially varying electric field will be sensitive to an electric dipole moment of the order of 10^-31 e cm. Thus a three- to four-order-of-magnitude improvement in the current limit would be possible with the construction of a decelerator capable of reducing the speed of a cold molecular beam of PbF. A similar a machine has already been built by others (Tarbutt et al, PRL 92 2004 (173002)) to decelerate a beam of YbF. The slowing techniques used are remarkably similar (up to an important sign difference) to those used in high energy physics. Thus the next dramatic improvement in the experimental limit on the electric EDM is likely to come from the accelerator physics community.