Calculation of the hadronic vacuum polarization contribution to the muon anomalous magnetic moment

TL;DR

This paper presents a highly precise lattice QCD+QED calculation of the leading-order hadronic vacuum polarization contribution to the muon anomalous magnetic moment, combining lattice data with experimental R-ratio data to improve accuracy.

Contribution

It provides the most precise lattice-based determination of the hadronic vacuum polarization contribution and includes the first lattice calculation of light-quark QED correction at physical pion mass.

Findings

Calculated $a_\mu^{\rm HVP~LO}$ with high precision

Combined lattice and experimental data for improved accuracy

First lattice QED correction for light quarks at physical pion mass

Abstract

We present a first-principles lattice QCD+QED calculation at physical pion mass of the leading-order hadronic vacuum polarization contribution to the muon anomalous magnetic moment. The total contribution of up, down, strange, and charm quarks including QED and strong isospin breaking effects is found to be $a_\mu^{\rm HVP~LO}=715.4(16.3)(9.2) \times 10^{-10}$, where the first error is statistical and the second is systematic. By supplementing lattice data for very short and long distances with experimental R-ratio data using the compilation of Ref. [1], we significantly improve the precision of our calculation and find $a_\mu^{\rm HVP~LO} = 692.5(1.4)(0.5)(0.7)(2.1) \times 10^{-10}$ with lattice statistical, lattice systematic, R-ratio statistical, and R-ratio systematic errors given separately. This is the currently most precise determination of the leading-order hadronic vacuum polarization contribution to the muon anomalous magnetic moment. In addition, we present the first lattice calculation of the light-quark QED correction at physical pion mass.