Hadronic contribution to the running QED coupling at the Z-boson mass scale

TL;DR

This paper updates a model-independent method to precisely determine the hadronic contribution to the QED coupling at the Z-boson mass scale, significantly reducing uncertainties with improved lattice QCD results.

Contribution

It introduces an improved, model-independent approach for calculating the hadronic contribution to the QED coupling at the Z-boson mass, utilizing recent lattice QCD data.

Findings

Calculated $ ext{Δα}_ ext{HAD}(M_Z^2)$ as 274.13(0.73)×10⁻⁴

Reduced uncertainty in the hadronic contribution using lattice QCD

Enhanced precision in the QED coupling at the Z-boson scale

Abstract

An update is described of a model independent method to determine the hadronic contribution to the QED running coupling at the Z-boson mass scale, $\Delta\alpha_{\text{HAD}}(M_{Z}^{2})$. The major source of uncertainty is from the contribution of the light quark vector current correlator at zero momentum. This uncertainty is substantially reduced using recently improved lattice QCD results for this correlator. The result is $\Delta\alpha_{\text{HAD}}(M_{Z}^{2})=274.13 (0.73)\, \times 10^{-4}$.