New constraints on time-reversal asymmetry from a search for a permanent electric dipole moment ofHg199

Abstract
A search for permanent electric dipole moment of Hg199 atoms has yielded the null result d(199Hg)=(0.7±1.5)×1026 e⋅cm, which improves by an order of magnitude the limits on several possible interactions that violate time-reversal symmetry. The experiment was performed by the use of optically pumped atomic oscillators to measure any shift in the NMR frequency of Hg199 (I=(1/2) produced by an external electric field.