Three-Loop Corrections to Lamb Shift in Muonium and Positronium

TL;DR

This paper computes three-loop radiative corrections to energy levels in muonium and positronium, aiming to improve theoretical predictions for upcoming high-precision spectroscopic measurements.

Contribution

It provides the first calculation of three-loop spin-independent corrections due to radiative insertions in two-photon exchange diagrams for muonium and positronium.

Findings

Corrections are significant for precision spectroscopy.

Results improve the accuracy of theoretical energy level predictions.

Potential impact on interpreting experimental measurements.

Abstract

We calculate hard spin-independent three-loop radiative corrections to energy levels in muonium and positronium which are due to radiative insertions in two-photon exchange diagrams. These corrections could be relevant for the new generation of precise $1S-2S$ and $2S-2P$ measurements in muonium and positronium.