A development of the CI + all-order method and application to the parity-nonconserving amplitude and other properties of Pb

TL;DR

This paper advances a combined configuration interaction and all-order coupled-cluster method to accurately compute atomic properties of lead, including parity-nonconserving amplitudes, confirming the standard model's predictions.

Contribution

The paper develops an improved CI + all-order method and applies it to atomic lead, significantly reducing uncertainties in PNC amplitude calculations.

Findings

Reduced uncertainty in PNC amplitude by a factor of two.

Calculated weak charge Q_W=-117(5), consistent with the standard model.

Provided accurate energy levels and hyperfine constants for lead.

Abstract

We have further developed and extended a method for calculation of atomic properties based on a combination of the configuration interaction and coupled-cluster approach. We have applied this approach to the calculation of different properties of atomic lead, including the energy levels, hyperfine structure constants, electric-dipole transition amplitudes, and E1 parity nonconserving (PNC) amplitude for the (6p^2) ^3P_0 - (6p^2) ^3P_1 transition. The uncertainty of the E1 PNC amplitude was reduced by a factor of two in comparison with the previous most accurate calculation [V.~A.~Dzuba et.al., Europhys. Lett. 7, 413 (1988)]. Our value for the weak charge Q_W=-117(5) is in agreement with the standard model prediction.