Search for a Permanent Electric Dipole Moment of the Mercury Atom

There has been exciting progress in recent years in the search for a permanent electric dipole moment (EDM) of an atom, a molecule, or the neutron. An EDM along the axis of spin can exist only if time reversal symmetry (T) is violated. Although such a dipole has not yet been detected, mainstream theories of possible new physics, such as Supersymmetry, predict the existence of EDMs within reach of modern experiments. Here I discuss the results of our new experimental search for a permanent electric dipole moment of (199)Hg utilizing a stack of four vapor cells. We find d((199)Hg) = (0.49c1.29(stst)c0.76(syst))x 10(-29) e cm, and interpret this as a new upper bound, d((199)Hg) < 3.1 x 1(T(-29)e cm (95% C.L.). This result improves our previous (199)Hg limit by a factor of 7, and can be used to set new constraints on CP violation in physics beyond the Standard Model.