Lattice Determination of the Anomalous Magnetic Moment of the Muon

We compute the leading hadronic contribution to the anomalous magnetic moment of the muon aHLO μ using two dynamical flavours of non-perturbatively O(a) improved Wilson fermions. By applying partially twisted boundary conditions we are able to improve the momentum resolution of the vacuum polarisation, an important ingredient for the determination of the leading hadronic contribution. We check systematic uncertainties by studying several ensembles, which allows us to discuss finite size effects and lattice artefacts. The chiral behavior of aHLO μ turns out to be non-trivial, especially for small pion masses.