Theory of the n=2 levels in muonic deuterium

TL;DR

This paper reviews the theoretical understanding of the energy levels in muonic deuterium, focusing on Lamb shift and hyperfine structure, to support upcoming experimental measurements and refine nuclear charge radius estimates.

Contribution

It provides a comprehensive comparison of existing QED and nuclear structure contributions, resolving discrepancies and identifying terms needing independent recalculation.

Findings

Reliable values and uncertainties for QED and nuclear contributions

Resolution of discrepancies in two-photon exchange contributions

Identification of problematic terms requiring recalculation

Abstract

The present knowledge of Lamb shift, fine- and hyperfine structure of the $\mathrm{2S}$ and $\mathrm{2P}$ states in muonic deuterium is reviewed in anticipation of the results of a first measurement of several $\mathrm{2S-2P}$ transition frequencies in muonic deuterium ($\mu\mathrm{d}$). A term-by-term comparison of all available sources reveals reliable values and uncertainties of the QED and nuclear structure-dependent contributions to the Lamb shift, which are essential for a determination of the deuteron rms charge radius from $\mu\mathrm{d}$. Apparent discrepancies between different sources are resolved, in particular for the difficult two-photon exchange contributions. Problematic single-sourced terms are identified which require independent recalculation.