Subtractions and the effective Salpeter term for the Lamb shift in muonic atoms with the nuclear spin I ≠ 1∕2

Abstract

While taking into account the nuclear-structure contributions to the Lamb shift, one has to make various subtractions for the two-photon exchange contributions. Such subtractions should be consistent with the structureless part of theory. We study here the subtractions for a two-body atomic systems which consist of a pointlike lepton (an electron or a muon) and a nucleus with spin 0, 1/2, and 1, and find the recoil contribution in order (Zα) 5 due to the subtractions for I = 0, 1. (The related contribution to the energy levels for I = 1/2 of order (Zα) 5 m is called the Salpeter term.