A New Method for the Evaluation of the Parity-Violating Electric Dipole 6 <i>S</i> → 7 <i>S</i> Amplitude in Atomic Cesium

Abstract

The parity-violating 6S → 7S E1pv amplitude in cesium is computed by a method which uses the information on the atomic wave functions near the nucleus contained in the empirical hyperfine splittings. We do not deal directly with the matrix elements of the e-nucleus p.v. potential, but we rescale them by the geometrical mean of the S and P states h.f.s. constants. As theoretical objects, the rescaled matrix elements offer many advantages: a) they show very little dependence upon the single-particle potential; b) they are practically insensitive to many-body effects described by a perturbation of the valence orbitals; c) the core polarization corrections are small, typically 4 to 5%. Our final result E1pv = 0.935 · 10-11 i|e|a0 Qw/N is affected by an experimental error (2%) and a theoretical one (3%) which ultimately could be pushed down to the 1% level.