Relativistic many-body calculation of parity-violating E1-amplitude for the 6S --> 7S transition in atomic cesium

The parity violating E1-amplitude for the 6S-7S transition in cesium has been calculated from first principles: <7S|D _z|6S> = (0.88 ± 0.03) × 10 ^-11 ( {-Q _W}/{N})(-iea _B) , where Q_W is the weak nuclear charge, N is the number of neutrons, and a_B is The Bohr radius. The experimental data from Bouchiat et al. make it possible to find Q_W = -73.4 ± 8.1 ± 6 and the Weinberg angle sin ²θ_W = 0.237 ± 0.036 ± 0.03. To control the accuracy, the energy levels, the fine and hyperfine structure intervals and the oscillator strenghts in the S-P transitions in Cs have been calculated.