Vacuum polarization and hadronic contribution to muon g-2 from lattice QCD

We compute the vacuum polarization on the lattice in quenched QCD using non-perturbatively improved Wilson fermions. Above Q(2) of about 2 GeV(2) the results are very close to the predictions of perturbative QCD. Below this scale we see signs of non-perturbative effects which we can describe by the use of dispersion relations. We use our results to estimate the light quark contribution to the muon's anomalous magnetic moment. We find the result 446(23) x 10(-10), where the error only includes statistical uncertainties. Finally we make some comments on the applicability of the operator product expansion to our data. (C) 2004 Elsevier B.V. All rights reserved.