Correlated many-body treatment of the Breit interaction with application to cesium atomic properties and parity violation

Corrections from the Breit interaction to basic properties of atomic Cs are determined in the framework of third-order relativistic many-body perturbation theory. The corrections to energies, hyperfine-structure constants, off-diagonal hyperfine 6S-7S amplitude, and electric-dipole matrix elements are tabulated. It is demonstrated that the Breit corrections to correlations are comparable to the Breit corrections at the Hartree-Fock level. Modification of the parity-nonconserving ~PNC! 6S-7S amplitude due to Breit interaction is also evaluated; the resulting weak charge of Cs shows no significant deviation from the prediction of the standard model of elementary particles. The neutron skin correction to the PNC amplitude is also estimated to be 20.2% with an error bound of 30% based on the analysis of recent experiments with antiprotonic atoms. The present work supplements publication @A. Derevianko, Phys. Rev. Lett. 85, 1618 ~2000!# with a discussion of the formalism and provides additional numerical results and updated discussion of parity violation.