Hadronic Contributions to the Muon g−2 from the Lattice

We present the most recent lattice results for the lowest-order hadronic contribution to the muon anomalous magnetic moment using 2+1 flavor improved staggered fermions, including simulations with a new light quark mass. A precise fit to the low-q2 region of the vacuum polarization is necessary to accurately extract the muon g−2. To obtain this fit, we use staggered chiral perturbation theory with the inclusion of the vector particles as resonances, to evaluate the vacuum polarization. We discuss the preliminary fit results and attendant systematic uncertainties, paying particular attention to the relative contributions of the pions and vector mesons.