title: Quantum electrodynamics in strong electric fields: the ground-state Lamb shift in hydrogenlike uranium.
abstract: 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.
authors.affiliation: Gesellschaft für Schwerionenforschung, 64291 Darmstadt, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Gumberidze
authors.forename: Th
authors.initials: T
authors.lastname: Stöhlker
authors.forename: D
authors.initials: D
authors.lastname: Banaś
authors.forename: K
authors.initials: K
authors.lastname: Beckert
authors.forename: P
authors.initials: P
authors.lastname: Beller
authors.forename: H F
authors.initials: HF
authors.lastname: Beyer
authors.forename: F
authors.initials: F
authors.lastname: Bosch
authors.forename: S
authors.initials: S
authors.lastname: Hagmann
authors.forename: C
authors.initials: C
authors.lastname: Kozhuharov
authors.forename: D
authors.initials: D
authors.lastname: Liesen
authors.forename: F
authors.initials: F
authors.lastname: Nolden
authors.forename: X
authors.initials: X
authors.lastname: Ma
authors.forename: P H
authors.initials: PH
authors.lastname: Mokler
authors.forename: M
authors.initials: M
authors.lastname: Steck
authors.forename: D
authors.initials: D
authors.lastname: Sierpowski
authors.forename: S
authors.initials: S
authors.lastname: Tashenov