g factor in a light two body atomic system: a determination of   fundamental constants to test QED
  Energy levels of a two-body atomic system in an external homogeneous magnetic field can be presented in terms of magnetic moments of their components, however, those magnetic moments being related to bound particles differ from their free values. Study of bound g factors in simple atomic systems are now of interest because of a recent progress in experiments on medium Z ions and of a new generation of muonium experiments possible with upcoming intensive muon sources. We consider bound corrections to the g factors in several atomic systems, experimental data for which are available in literature: hydrogen, helium-3 ion, muonium, hydrogen-like ions with spinless nuclei with medium Z. 
S. G. Karshenboim and V. G. Ivanov