Parity violation in two-photon J=0-to-1 transitions: Analysis of   systematic errors
  We present an analysis of systematic sources of uncertainty in a recently proposed scheme for measurement of nuclear-spin-dependent atomic parity violation using two-photon J=0-to-1 transitions driven by collinear photons of the same frequency in the presence of a static magnetic field. Two important sources of uncertainty are considered: misalignment of applied fields, and stray electric and magnetic fields. The parity-violating signal can be discriminated from systematic effects using a combination of field reversals and analysis of the Zeeman structure of the transition. 
D. R. Dounas-Frazer, K. Tsigutkin, D. English, and D. Budker
physics.atom-ph