Quantum electrodynamics in strong electric fields: the ground-state Lamb shift in hydrogenlike uranium.
X-ray spectra following radiative recombination of free electrons with bare uranium ions (U92+) were measured at the electron cooler of the ESR storage ring. The most intense lines observed in the spectra can be attributed to the characteristic Lyman ground-state transitions and to the recombination of free electrons into the K shell of the ions. Our experiment was carried out by utilizing the deceleration technique which leads to a considerable reduction of the uncertainties associated with Doppler corrections. This, in combination with the 0 degree observation geometry, allowed us to determine the ground-state Lamb shift in hydrogenlike uranium (U91+) from the observed x-ray lines with an accuracy of 1%. The present result is about 3 times more precise than the most accurate value available up to now and provides the most stringent test of bound-state quantum electrodynamics for one-electron systems in the strong-field regime.
Gumberidze
A
A
Gesellschaft für Schwerionenforschung, 64291 Darmstadt, Germany.
Stöhlker
Th
T
Banaś
D
D
Beckert
K
K
Beller
P
P
Beyer
H F
HF
Bosch
F
F
Hagmann
S
S
Kozhuharov
C
C
Liesen
D
D
Nolden
F
F
Ma
X
X
Mokler
P H
PH
Steck
M
M
Sierpowski
D
D
Tashenov
S
S