Nonperturbative QCD corrections to electroweak observables

TL;DR

This paper discusses how recent lattice QCD methods can accurately compute nonperturbative QCD corrections to electroweak observables, improving theoretical predictions for quantities like the muon magnetic moment.

Contribution

It introduces a new lattice QCD approach for calculating key hadronic corrections to electroweak observables, enhancing the precision of theoretical estimates.

Findings

Lattice QCD can compute leading-order QCD corrections to muon magnetic moment.

New methods improve calculations of electromagnetic coupling running.

Potential applications include determining the strong coupling constant.

Abstract

Nonperturbative QCD corrections are important to many low-energy electroweak observables, for example the muon magnetic moment. However, hadronic corrections also play a significant role at much higher energies due to their impact on the running of standard model parameters, such as the electromagnetic coupling. Currently, these hadronic contributions are accounted for by a combination of experimental measurements, effective field theory techniques and phenomenological modeling but ideally should be calculated from first principles. Recent developments indicate that many of the most important hadronic corrections may be feasibly calculated using lattice QCD methods. To illustrate this, we will examine the lattice computation of the leading-order QCD corrections to the muon magnetic moment, paying particular attention to a recently developed method but also reviewing the results from other calculations. We will then continue with several examples that demonstrate the potential impact of the new approach: the leading-order corrections to the electron and tau magnetic moments, the running of the electromagnetic coupling, and a class of the next-to-leading-order corrections for the muon magnetic moment. Along the way, we will mention applications to the Adler function, which can be used to determine the strong coupling constant, and QCD corrections to muonic-hydrogen.