Remarks on higher-order hadronic corrections to the muon g-2
  Recently, it was shown that insertions of hadronic vacuum polarization at O(alpha^4) generate non-negligible effects in the calculation of the anomalous magnetic moment of the muon. This result raises the question if other hadronic diagrams at this order might become relevant for the next round of g-2 measurements as well. In this note we show that a potentially enhanced such contribution, hadronic light-by-light scattering in combination with electron vacuum polarization, is already sufficiently suppressed. 
Gilberto Colangelo, Martin Hoferichter, Andreas Nyffeler, Massimo   Passera, Peter Stoffer
hep-ph hep-ex nucl-th