We have evaluated the hadronic contribution to the muon anomaly arising from diagrams containing hadronic light-by-light scattering subdiagrams using two different models. Our result is 49(5)×${10}^{\mathrm{-}11}$ which disagrees with an earlier calculation. We have also improved the contribution of the hadronic vacuum polarization diagrams to second- and fourth-order QED diagrams, using the latest experimental data. The results are 707(19)×${10}^{\mathrm{-}10}$ and -90(5)×${10}^{\mathrm{-}11}$, respectively. The complete hadronic contribution is thus 703(19)×${10}^{\mathrm{-}10}$. The remaining error comes predominantly from the experimental inputs needed for evaluating the hadronic vacuum polarization effect.

• Received 10 September 1984

DOI:https://doi.org/10.1103/PhysRevD.31.2108