The strange and charm quark contributions to the anomalous magnetic moment (g -2) of the muon from current-current correlators

TL;DR

This paper introduces a lattice QCD method using Padé approximants to accurately compute the strange and charm quark contributions to the muon's anomalous magnetic moment (g-2) from current-current correlators.

Contribution

It presents a novel technique employing Padé approximants and time-moments of correlators to determine hadronic vacuum polarization contributions to g-2 from lattice QCD data.

Findings

Method accurately reconstructs the Adler function from derivatives at zero momentum.

Validated approach on MILC ensembles with multiple lattice spacings and quark masses.

Provides a new avenue for precise theoretical g-2 calculations.

Abstract

We describe a new technique (presented in arXiv:1403.1778) to determine the contribution to the anomalous magnetic moment (g-2) of the muon coming from the hadronic vacuum polarisation using lattice QCD. Our method uses Pad\'{e} approximants to reconstruct the Adler function from its derivatives at $q^2=0$. These are obtained simply and accurately from time-moments of the vector current-current correlator at zero spatial momentum. We test the method using strange quark correlators calculated on MILC Collaboration's $n_f$ = 2+1+1 HISQ ensembles at multiple values of the lattice spacing, multiple volumes and multiple light sea quark masses (including physical pion mass configurations).