1sLamb Shift in Hydrogenlike Uranium Measured on Cooled, Decelerated Ion Beams

Abstract

The Lyman- alpha transitions of hydrogenlike uranium associated with electron capture were measured in collisions of stored bare U (92+) ions with gaseous targets at the storage ring ESR. By applying the deceleration technique, the experiment was performed at slow collision energies in order to reduce the uncertainties associated with Doppler corrections. From the measured centroid energies, a ground state Lamb shift of 468 eV+/-13 eV is deduced which gives the most precise test of quantum electrodynamics for a single electron system in the strong field regime. In particular, the technique applied paves the way towards the 1 eV precision regime.

Measurement of the Two-Loop Lamb Shift in LithiumlikeU89+

“…For the 1s ground level in U 91+ , the calculated value is 1.55 eV. Measurements sensitive to the 1s QED term of hydrogenlike uranium U 91+ , the heaviest naturally occurring element, have achieved an accuracy of 13 eV [2]. This corresponds to a fractional accuracy of 5% when compared to the total 1s QED contribution of about 270 eV, but it is insensitive to two-loop corrections.…”

Two-time Green's function method in quantum electrodynamics of high-Z few-electron atoms

“…The uncertainty of the Dirac binding energy results from the uncertainty of the Rydberg constant [146]. As can be deduced from the table, the present status of the experimental precision on the ground-state Lamb shift in hydrogenlike uranium [147][148][149] provides a test of QED in first order in α on the level of about 5%.…”

“…Let us consider the function G(E ′ , E) defined as [39,112] 198.81(38) First-order SE [123] 355.05 First-order VP [119] −88.60 Second-order QED ± 1.5 Nuclear recoil [141] 0.46 Nuclear polarization [144,145] −0.20(10) Lamb shift theory 465.52(39) ± 1.5 Lamb shift experiment [149] 468 (13) [39] 1881.50(7) Experiment [152] 1876 (14) TABLE III. The 2p 1/2 − 2s transition energy in 238 U 89+ , in eV.…”

Screened Self-energy Correction to the 2p[sub 3∕2]–2s Transition Energy in Li-Like Ions

“…While the simplicity of the hydrogen isoelectronic sequence makes it ideal for theoretical investigations, the achieved experimental accuracy is by far better in few-electron systems. In particular, the Lamb shift in H-like uranium is presently known at the 3% level [1], whereas the 2p 3/2 -2s splitting in Li-like bismuth was measured to be E 2p 3/2 − E 2s = 2788.139 (9) eV ,…”