Hadronic contribution to the muon anomalous magnetic moment to   next-to-next-to-leading order
  We compute the next-to-next-to-leading order hadronic contribution to the muon anomalous magnetic moment originating from the photon vacuum polarization. The corresponding three-loop kernel functions are calculated using asymptotic expansion techniques which lead to analytic expressions. Our final result, $a_\mu^{\rm had,NNLO} = 1.24 \pm 0.01 \times 10^{-10}$, has the same order of magnitude as the current uncertainty of the leading order hadronic contribution and should thus be included in future analyses. 
Alexander Kurz, Tao Liu, Peter Marquard, Matthias Steinhauser
hep-ph