g Factor of Lithiumlike Silicon and Calcium: Resolving the Disagreement between Theory and Experiment

TL;DR

This paper improves theoretical calculations of the bound-electron g factor in lithiumlike silicon and calcium, resolving previous discrepancies with experimental measurements and providing the most accurate predictions to date.

Contribution

It introduces high-precision QED calculations within the extended Furry picture, resolving the disagreement between theory and experiment for lithiumlike silicon and calcium.

Findings

Enhanced agreement between theory and experiment for lithiumlike silicon.

Most accurate theoretical prediction for lithiumlike calcium.

Significant reduction of previous discrepancies in g factor values.

Abstract

The bound-electron g factor is a stringent tool for tests of the Standard Model and the search for new physics. The comparison between an experiment on the g factor of lithiumlike silicon and the two recent theoretical values revealed the discrepancies of $1.7\sigma$ [D. A. Glazov $\textit{et al}$., Phys. Rev. Lett. $\textbf{123}$, 173001 (2019)] and $5.2\sigma$ [V. A. Yerokhin $\textit{et al}$., Phys. Rev. A $\textbf{102}$, 022815 (2020)]. To identify the reason for this disagreement, we accomplish large-scale high-precision computation of the interelectronic-interaction and many-electron QED corrections. The calculations are performed within the extended Furry picture of QED, and the dependence of the final values on the choice of the binding potential is carefully analyzed. As a result, we significantly improve the agreement between the theory and experiment for the g factor of lithiumlike silicon. We also report the most accurate theoretical prediction to date for lithiumlike calcium, which perfectly agrees with the experimental value.