Vacuum polarization and finite-nuclear-size effects in the two-photon decay of hydrogenlike ions

Investigation of two-photon 2s -> 1s decay in one-electron and one-muon ions

“…In the case of the muon ions, the main radiative correction is the electron vacuum polarization correction, which can be taken into account within the Uehling approximation. For one-electron ions, the nuclear recoil correction and the radiative corrections were neglected because of their smallness [31].…”

“…For the one-electron ions, the one-photon transition probabilities are listed in [48], the nuclear size corrections are considered in [49]. The two-photon transitions for the 2s-electron state were investigated by many authors [6,9,11,12,31].…”

“…For the one-electron ions the radiative corrections to the transition probabilities are investigated in works [31][32][33].…”

“…The dominant part of the electron self-energy radiative correction to the two-photon transition probabilities were calculated in [32,33]. The vacuum polarization corrections (in the Uehling approximation) are presented in [31]. Contribution of the negative continuum of the Dirac spectrum to the total and differential transition probabilities is investigated in [9] and [11], respectively.…”

“…We found that the radiative decay of the 2s state in the electron and muon ions is qualitatively different. In particular, for one-electron ions, the only cascade channel is 2s → 2p 1/2 → 1s, which is negligibly weak, mainly due to the small energy difference between 2s and 2p 1/2 states [31].…”