The hyperfine anomaly in heavy atoms and its role in precision atomic searches for new physics

TL;DR

This paper calculates hyperfine anomalies in heavy atoms to improve nuclear magnetization models, which are crucial for precision atomic tests of fundamental physics, especially in atoms like cesium used for symmetry violation studies.

Contribution

It validates the nuclear single-particle model for hyperfine anomaly calculations in cesium, enhancing the accuracy of atomic parity violation analyses.

Findings

Supports the nuclear single-particle model over the uniform ball model

Demonstrates the model's validity for cesium hyperfine anomaly

Highlights importance of accurate nuclear magnetization modelling

Abstract

We report on our calculations of differential hyperfine anomalies in the nuclear single-particle model for a number of atoms and ions of interest for studies of fundamental symmetries violations. Comparison with available experimental data allows one to discriminate between different nuclear magnetization models, and this data supports the use of the nuclear single-particle model over the commonly-used uniform ball model. Accurate modelling of the nuclear magnetization distribution is important for testing atomic theory through hyperfine comparisons. The magnetization distribution must be adequately understood and modelled, with uncertainties well under the atomic theory uncertainty, for hyperfine comparisons to be meaningful. This has not been the case for a number of atoms of particular interest for precision studies, including Cs. Our work demonstrates the validity of the nuclear single-particle model for Cs, and this has implications for the theory analysis of atomic parity violation in this atom.