Measurement Of The Permanent Electric Dipole Moment Of The Xe-129 Atom

We report on a measurement of the CP-violating permanent electric dipole moment (EDM) of the neutral Xe-129 atom. Our experimental approach is based on the detection of the free precession of co-located nuclear spin-polarized He-3 and Xe-129 samples. The EDM measurement sensitivity benefits strongly from long spin coherence times of several hours achieved in diluted gases and homogeneous weak magnetic fields of about 400 nT. A finite EDM is indicated by a change in the precession frequency, as an electric field is periodically reversed with respect to the magnetic guiding field. Our result (-4.7 +/- 6.4) x 10(-28)e cm, is consistent with zero and is used to place a new upper limit on the Xe-129 EDM: vertical bar d(Xe)vertical bar < 1.5 x 10(-27) e cm (95% C.L.). We also discuss the implications of this result for various CP-violating observables as they relate to theories of physics beyond the standard model.