Calculation of parity nonconservation in cesium and possible deviation from the Standard Model

TL;DR

This paper presents a highly accurate calculation of parity nonconservation in cesium, refining previous results and confirming consistency with the Standard Model within experimental and theoretical uncertainties.

Contribution

The authors improved the numerical accuracy of the cesium parity nonconservation calculation and included Breit interaction and radiative corrections for the first time.

Findings

Calculated E_{PNC} with 0.7% accuracy

Derived nuclear weak charge Q_{W}=-72.39 with 0.4% experimental error

Found no significant deviation from the Standard Model

Abstract

We have calculated the 6s-7s parity nonconserving E1 transition amplitude (E_{PNC}) in cesium. This calculation has been performed with higher numerical accuracy than our 1989 calculation [V.A. Dzuba, V.V. Flambaum, and O.P. Sushkov, Phys. Lett. A {\bf 141}, 147]. Also the Breit interaction has been included and the radiative corrections estimated. Our final result is E_{PNC}=0.902 (1 +/- 0.7%)iea_{B}(Q_{W}/N). This represents an improvement in the accuracy of the calculation from the 1% error claimed in 1989. This result corresponds to a nuclear weak charge for Cs, Q_{W}=-72.39 (1 +/- 0.4% (exp) +/- 0.7% (theory)). We conclude that there is no significant deviation from the Standard Model value -73.09(3).