Model-independent parametrization of the hadronic vacuum polarization and g-2 for the muon on the lattice

TL;DR

This paper introduces a model-independent method to extrapolate the hadronic vacuum polarization in lattice QCD calculations, improving the precision of the muon g-2 theoretical prediction by reducing model dependence.

Contribution

The paper presents a novel, model-independent parametrization technique for the hadronic vacuum polarization, addressing limitations of traditional vector meson dominance models.

Findings

Initial tests show promising accuracy in extrapolation.

Method reduces model dependence in lattice QCD calculations.

Potential to improve muon g-2 theoretical estimates.

Abstract

The leading hadronic contribution to the muon anomalous magnetic moment is given by a weighted integral over euclidean momentum of the hadronic vacuum polarization. This integral is dominated by momenta of order the muon mass. Since the finite volume in lattice QCD makes it difficult to compute the vacuum polarization at a large number of low momenta with high statistics (combined with the fact that one cannot compute it at zero momentum), a parametrization of the vacuum polarization is required to extrapolate the data. A much used functional form is based on vector meson dominance, which introduces model dependence into the lattice computation of the magnetic moment. Here we introduce a model-independent extrapolation method, and present a few first tests of this new method.