Contribution of hadronic light-by-light scattering to the hyperfine structure of muonium

TL;DR

This paper calculates the hadronic light-by-light scattering contribution to muonium's hyperfine structure using experimental form factor data, considering various meson exchanges to refine theoretical predictions.

Contribution

It provides a detailed calculation of hadronic light-by-light effects on muonium hyperfine splitting, including multiple meson exchange contributions, which was not comprehensively done before.

Findings

Quantified the hadronic light-by-light contribution to muonium hyperfine structure.

Included pseudoscalar, axial vector, scalar, and tensor meson exchanges.

Enhanced the precision of theoretical predictions for muonium hyperfine splitting.

Abstract

The contribution of hadronic scattering of light-by-light to the hyperfine structure of muonium is calculated using experimental data on the transition form factors of two photons into a hadron. The amplitudes of interaction between a muon and an electron with horizontal and vertical exchange are constructed. The contributions due to the exchange of pseudoscalar, axial vector, scalar and tensor mesons are taken into account.