Paper detail

Parity violation in atomic ytterbium: experimental sensitivity and systematics

We present a detailed description of the observation of parity violation in the 1S0-3D1 408-nm forbidden transition of ytterbium, a brief report of which appeared earlier. Linearly polarized 408-nm light interacts with Yb atoms in crossed E- and B-fields. The probability of the 408-nm transition contains a parity violating term, proportional to (Elight . B)[(E x Elight) . B], arising from interference between the parity violating amplitude and the Stark amplitude due to the E-field (Elight is the electric field of the light). The transition probability is detected by measuring the population of the 3P0 state, to which 65% of the atoms excited to the 3D1 state spontaneously decay. The population of the 3P0 state is determined by resonantly exciting the atoms with 649-nm light to the 6s7s 3S1 state and collecting the fluorescence resulting from its decay. Systematic corrections due to E-field and B-field imperfections are determined in auxiliary experiments. The statistical uncertainty is dominated by parasitic frequency excursions of the 408-nm excitation light due to imperfect stabilization of the optical reference with respect to the atomic resonance. The present uncertainties are 9% statistical and 8% systematic. Methods of improving the accuracy for the future experiments are discussed.