New correction to Lamb shift induced by one-loop polarization insertions in the radiative electron factor

Abstract

A radiative correction of order α 2( Zα) 5 m to the Lamb shift induced by polarization insertions in the radiative electron factor is obtained. This correction arises from a gauge invariant set of diagrams which contain all one-loop polarization insertions in the radiative photon attached by both ends to the electron line with two external Coulomb lines. A new contribution to the Lamb shift in an arbitrary hydrogen-like ion is equal to −0.073( α 2( Zα) 5/( πn 3)) m for any S-level with the principal quantum number n. For hydrogen itself we obtain a correction −0.39 kHz for the 2S state.