New Polarization Operator Contributions to Lamb Shift and Hyperfine Splitting

Abstract: We calculate radiative corrections to the Lamb shift of order $\alpha^3(Z\alpha)^5m$ and radiative corrections to hyperfine splitting of order $\alpha^3(Z\alpha)E_F$ generated by the diagrams with insertions of radiative photons and electron polarization loops in the graphs with two external photons. We also obtain the radiative-recoil correction to hyperfine splitting in muonium generated by the diagrams with the $\tau$ polarization loop.