The contribution of pseudoscalar and axial-vector mesons to hyperfine structure of muonic hydrogen

TL;DR

This paper calculates the impact of light pseudoscalar and axial-vector mesons on the hyperfine structure of muonic hydrogen, highlighting their significance for precise experimental comparisons.

Contribution

It introduces a novel calculation of meson contributions to muonic hydrogen hyperfine splitting using a quasipotential approach and experimental form factor data.

Findings

Meson contributions significantly affect hyperfine splitting.

Numerical estimates align with experimental precision.

The approach incorporates QCD asymptotics and form factor data.

Abstract

In the framework of the quasipotential method in quantum electrodynamics we calculate the contribution of light pseudoscalar (PS) and axial-vector (AV) mesons to the interaction operator of a muon and a proton in muonic hydrogen atom. The coupling of mesons with the muon is via two-photon intermediate state. The parametrization of the transition form factor of two photons into PS and AV mesons, based on the experimental data on the transition form factors and QCD asymptotics, is used. Numerical estimates of the contributions to the hyperfine structure of the spectrum of the S and P levels are presented. It is shown that such contribution to the hyperfine splitting in muonic hydrogen is rather important for a comparison with precise experimental data.