Blundell Sa

Calculations of the parity non-conserving 6s→7s transition in caesium

SummaryThe electroweak interaction between electrons and nucleons destroys the mirror symmetry of an atom. The size of the effect depends on the weak interaction constants as well as on the atomic structure. Small-scale experiments studying atomic parity non-conservation can thus give a quantitative test of the standard model for the electro-weak interaction — provided the atomic structure is sufficiently well understood. The increasing experimental accuracy, in particular for Cs, raises new demands on atomic theory. The various contributions to the parity non-conserving electric dipole transition matrix element are discussed together with the methods used to calculate them. The uncertainty in the atomic calculation is estimated. A discussion of radiative corrections with emphasis on the role of the top quark mass is also given.

Relativistic many-body calculations of oscillator strengths for sodium-like ions

Abstract Relativistic many-body perturbation theory is applied to calculate oscillator strengths for the components of the resonant 3p-3s doublets in sodium-like ions with nuclear charges ranging from Z = 11−29. The present calculations of the multiplet averaged oscillator strengths are in excellent agreement with previous nonrelativistic MCHF calculations. Discrepancies of order ten percent between measured oscillator strengths and ab initio Dirac-Hartree-Fock calculations for highly-ionized members of the sequence are resolved, but a one-percent discrepancy between theory and experiment remains for neutral sodium.

Atomic structure calculations associated with PNC experiments in atomic cesium

Accurate atomic many-body calculations of the parity nonconserving 6s → 7s dipole amplitude in atomic cesium are described. These calculations lead to the value -0.905(9) × 10-11i|e|a0(-Qw/N) for the 6s → 7s amplitude. Combining this value with the measured amplitude leads to the value QW = 71.1 ± 1.6 ± 0.9 for the weak charge, where the first error is from the measurement and the second is from the calculation. Implications of this result for particle physics are discussed.