Parity violation in atoms induced by radiative corrections

Abstract

We discuss the radiative corrections that induce a parity-violating electron-nucleus interaction in gauge theories. These higher-order effects are shown to be much larger than one might anticipate in a wide class of models. In particular, for an SU(2) × U(1) gauge model in which the electron's neutral-current coupling is pure vector, they lead to an optical rotation in bismuth which is about 11% as large as that predicted by the standard Weinberg-Salam model and opposite in sign—an experimentally testable consequence. Similar results are also found for an ${\mathrm{SU}}_L\mathrm{}\left(2\right)\mathrm{}\times {\mathrm{SU}}_R\mathrm{}\left(2\right)\mathrm{}\times \mathrm{U}\mathrm{}\left(1\right)\mathrm{}$ model in which parity-violating neutral currents are naturally absent in lowest order. General formulas for the dominant radiative corrections which are applicable to most models are presented. The relevance of our results for experiments on ordinary hydrogen and deuterium is also discussed.