A new strategy for evaluating the LO HVP contribution to $(g-2)_\mu$ on the lattice

Abstract

A highly physical model of the subtracted $I=1$ vector polarization, obtained using a dispersive representation with precise hadronic $\tau$ decay data as input, is used to investigate systematic issues in the lattice evaluation of the leading order hadronic vacuum polarization contribution to the anomalous magnetic moment of the muon. The model is also employed to study possible resolutions of these problems. A hybrid approach to analyzing lattice data, involving low-order Pad\'e, low-degree conformal-variable polynomial, or supplemented NNLO ChPT fits for $Q^2$ below $\sim 0.1-0.2$ GeV$^2$ and direct numerical integration of lattice data above this point, is shown to bring the systematic issues identified under control at the sub-$1\%$ level.