Light-quark connected intermediate-window contributions to the muon $g-2$ hadronic vacuum polarization from lattice QCD

TL;DR

This paper reports a lattice QCD calculation of the light-quark connected contribution to specific window observables related to the muon g-2 hadronic vacuum polarization, providing precise estimates with systematic uncertainty analysis.

Contribution

It introduces a novel lattice-QCD approach using multiple effective-field-theory schemes and Bayesian model averaging for robust systematic uncertainty estimation.

Findings

Calculated intermediate window contribution: 206.6(1.0)×10^{-10}

Calculated W2 window contribution: 100.7(3.2)×10^{-10}

Employs multiple lattice spacings and quark masses for accuracy

Abstract

We present a lattice-QCD calculation of the light-quark connected contribution to window observables associated with the leading-order hadronic vacuum polarization contribution to the anomalous magnetic moment of the muon, $a_\mu^{\mathrm{HVP,LO}}$. We employ the MILC Collaboration's isospin-symmetric QCD gauge-field ensembles, which contain four flavors of dynamical highly-improved-staggered quarks with four lattice spacings between $a\approx 0.06$-$0.15$~fm and close-to-physical quark masses. We consider several effective-field-theory-based schemes for finite-volume and other lattice corrections and combine the results via Bayesian model averaging to obtain robust estimates of the associated systematic uncertainties. After unblinding, our final results for the intermediate and ``W2'' windows are $a^{ll,{\mathrm W}}_{\mu}(\mathrm{conn.})=206.6(1.0) \times 10^{-10}$ and $a^{ll,\mathrm {W2}}_{\mu}(\mathrm{conn.}) = 100.7(3.2)\times 10^{-10}$, respectively.