Test of electron screening and vacuum polarization in heavy muonic atoms

Abstract

Energies of higher # X-rays have been measured in l~ natHg and 2~ to test the vacuum polarization correction and the electron screening effect in heavy muonic atoms. For tests of the energy calibration delayed nuclear 7-rays from the #-capture reaction were used. The experimental data agree to better than 4% with self-consistent Hartree-Fock calculations of the electron screening. Transitions which are sensitive to the vacuum polarization correction mainly, verify the calculations to better than 1.5 %. Comparing all at present existing experiments with latest calculations no significant deviation of more than 0.7 % of the vacuum polarization correction can be deduced.

Reduced theoretical error for He+4 spectroscopy

“…Indeed, experiments in the 1970s found a discrepancy between theoretical and measured values for certain transitions in heavy muonic atoms [3,4]. This motivated much research, and after a few years improvements in the theory [5][6][7][8] and in experiments [9,10] resolved the discrepancy and improved our understanding of QED [11]. Today a very similar situation can be found in the 'proton-radius' problem [15], wherein the root-mean-squared charge radius inferred from the leading nuclear contributions to atomic energy shifts in Hydrogen and muonic Hydrogen appears to depend on the flavour of the orbiting lepton.…”

Precision measurement of the muonic 5-4 transitions in Pb and 4-3 transitions in ba as a test for the validity of QED

“…No deviation of such transition energies from calculation has ever been measured. On the contrary, Vuilleumier et al [13] have demonstrated that the calculations coincide with experiment for all transitions between 100keV and 400keV in the case of Rh, Hg, and T1. The muonic X-rays used as calibration standards are listed in The energies given for the #-Ba and /~-Pb lines are those of the strongest component of the fine-structure multiplet.…”

Contribution of the exact Breit operator plus the electron state-dependent screening to the multiplet and fine structure of muon-electron atoms

“…Due to the radial distribution of the electrons about 85 % of the screening originates from the two I s electrons as compared with the total screening of all 81 electrons in Pb. An analysis has shown that in reality nearly always full inner shells [11,[14][15][16] have to be assumed when the muon transition occurs. This is well understood since the mean lifetime of an l s vacancy in Pb is of the order of 10-17s, due to the refilling of np electrons [17], whereas the radiative muon transition time for the 5-4 and 6-5 transition is at least slower by a factor of 5 and 10, respectively [18].…”