Testing high-Z QED with SuperEBIT: An estimate of the two-loop Lamb shift based on a measurement of the – transition in

Beiersdörfer, P.

doi:10.1016/j.radphyschem.2005.12.047

Cited by 3 publications

(3 citation statements)

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“…To do so, we scale the two-loop QED of the 2s level the same way theory predicts the scaling for the one-loop QED term [40]. This means we have to multiply the results for the 1s 2 2p 1/2 → 1s 2 2s 1/2 transition by −6.39 and obtain −1.27±0.45 eV.…”

Section: Figmentioning

confidence: 99%

Precision energy-level measurements and QED of highly charged ions

Beiersdörfer¹

2009

Can. J. Phys.

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A review is given of measurements involving the K-shell (np → 1s) transitions of hydrogenlike ions. In many experiments carried out, for example, on electron-beam ion traps and tokamaks, the calculated energies of the Lymanseries lines are utilized as calibration standards for measuring the energies of lines from more complex ions. Examples given include measurements of the transition energies of L-shell lines in neonlike ions. The Lyman lines of low-Z ions are also used as a bootstrap for measuring the contributions of quantum electrodynamics (QED) in very high-Z ions, such as U 81+ and U 89+ . The lowest energy member of the Lyman series, Lyman-α, is commonly the target of absolute-energy measurements so as to test the reliability of the calculations of atomic structure in general and of the 1s QED terms in particular. A review of 42 measurements of 1s QED measurements indicates an apparent bias toward wanting to agree with calculations. PACS Nos.: 32.30. Rj, 31.30.Jv, 12.20.−m Résumé : Nous passons en revue des mesures impliquant les transitions dans la couche K (np → 1s) dans les ions de type hydrogène. Dans plusieurs expériences, utilisant par exemple des pièges ioniques à faisceau d'électrons ou des tokamaks, les énergies calculées pour les lignes de la série Lyman sont utilisées comme standard de calibration pour mesurer les énergies de lignes dans des ions plus complexes. Des exemples incluent la mesure de lignes dans la couche L d'ions de type néon. Les lignes Lyman d'ions de faible Z sont aussi utilisées comme point de départ pour mesurer les effets de l'électrodynamique quantique (QED) dans les ions de Z élevé, comme U 81+ et U 89+ . L'élément de plus basse énergie de la série Lyman, Lyman-α, est souvent le sujet de mesures absolues en énergie, de façon à pouvoir tester la validité de calculs en structure atomique en général et en particulier du terme 1s en QED. Une révision de 42 mesures du 1s en QED indique un biais résultant d'un désir d'être en accord avec les valeurs calculées.[Traduit par la Rédaction]

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Section: Figmentioning

confidence: 99%

Precision energy-level measurements and QED of highly charged ions

Beiersdörfer¹

2009

Can. J. Phys.

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“…(45) recent measurement of the 2s 1/2 -2p 1/2 transition in lithiumlike U 89+ on the Livermore SuperEBIT electron beam ion trap [44], which we discuss in more detail below, allowed us to make the first such test of two-loop QED in hydrogen-like U 91+ . As shown in [44,47] and summarized in table 1, the measurement gives a value of 1.27 (45) eV for the two-loop contribution to the 1s level. This is a test of the predicted twoloop contribution at the 33% level.…”

Section: Testing Two-loop Diagrams In Hydrogen-like Uraniummentioning

confidence: 90%

“…In fact, using the result from the 2s two-loop QED determination we can already determine a value of −1.27 eV for the two-loop QED in 1s [44,47] as we have mentioned in section 3. This value compares very favourably to the value calculated by Yerokhin et al [46].…”

Section: Contributing Term Valuementioning

confidence: 96%

Testing QED and atomic-nuclear interactions with high-Zions

Beiersdörfer

2010

J. Phys. B: At. Mol. Opt. Phys.

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Measurements of high-Z hydrogen-like ions have not yet been able to compete with the ultra-high precise test of quantum electrodynamics (QED) carried out using atomic hydrogen. However, recent advances in theory and experiment have enabled measurements involving high-Z lithium-like ions to test two-loop QED at a level similar to that achieved with atomic hydrogen. Tests of two-loop QED are limited in both cases by the uncertainties in the finite nuclear size, i.e. the uncertainties associated with the proton charge radius and the finite size of high-Z nuclei, respectively. Future experiments employing high-Z ions are described that might go beyond the present limitations. Measurements of the hyperfine splitting in highly charged ions cannot readily be described by theory, in part because of poor understanding of the finite nuclear magnetization radius. The discrepancy between measurements and theory leaves open the possibility of new physics not yet addressed by our current understanding of atomic-nuclear interactions.

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High resolution flat crystal spectrometer for the Shanghai EBIT

Xiao

Gao

Zhang

et al. 2008

Review of Scientific Instruments

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We report on a high resolution flat crystal spectrometer designed for the Shanghai EBIT. Its energy range is from 0.5 to 10 keV. Three crystals can be installed in the vacuum chamber simultaneously, and its effective Bragg angle can be covered from 15 degrees to 75 degrees . A vacuum version charge-coupled device detector is used for detection of photons. An energy resolution under 1 eV was reached in measurements of the 4.5 keV Kalpha(1) line by using an x-ray generator with a titanium anode. The spectrometer was also tested to operate well on the Shanghai EBIT by observing the lines of tungsten at around 3.2 keV.

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Testing high-Z QED with SuperEBIT: An estimate of the two-loop Lamb shift based on a measurement of the – transition in

Cited by 3 publications

References 37 publications

Precision energy-level measurements and QED of highly charged ions

Precision energy-level measurements and QED of highly charged ions

Testing QED and atomic-nuclear interactions with high-Zions

High resolution flat crystal spectrometer for the Shanghai EBIT

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