Helium-like titanium x-ray spectrum as a probe of QED computation

Payne, A T; Chantler, Christopher T.; Kinnane, M. N.; Gillaspy, John D.; Hudson, Lawrence T.; Smale, L. F.; Henins, Albert; Kimpton, Justin A.; Takács, Endre

doi:10.1088/0953-4075/47/18/185001

Cited by 20 publications

(18 citation statements)

References 36 publications

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“…Four of the lowest levels, 1s2p 1 P 1 , 1s2p 3 P 2 , 1s2p 3 P 1 , and 1s2s 3 S 1 , are often used to test QED effects in helium-like ions (Chantler et al 2000;Bruhns et al 2007;Kubiček et al 2009Kubiček et al , 2013Amaro et al 2012;Chantler et al 2012;Rudolph et al 2013;Schlesser et al 2013;Kasthurirangan et al 2013;Payne et al 2014;Beiersdorfer & Brown 2015;Epp et al 2015). In Fig.…”

Section: Energy Levelsmentioning

confidence: 99%

Energy levels and transition rates for helium-like ions withZ = 10–36

Guo

Wang

et al. 2016

A&A

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Aims. Helium-like ions provide an important X-ray spectral diagnostics in astrophysical and high-temperature fusion plasmas. An interpretation of the observed spectra provides information on temperature, density, and chemical compositions of the plasma. Such an analysis requires information for a wide range of atomic parameters, including energy levels and transition rates. Our aim is to provide a set of accurate energy levels and transition rates for helium-like ions with Z = 10-36. Methods. The second-order many-body perturbation theory (MBPT) was adopted in this paper. To support our MBPT results, we performed an independent calculation using the multiconfiguration Dirac-Hartree-Fock (MCDHF) method. Results. We provide accurate energies for the lowest singly excited 70 levels among 1snl (n ≤ 6, l ≤ (n − 1)) configurations and the lowest doubly excited 250 levels arising from the K-vacancy 2ln l (n ≤ 6, l ≤ (n − 1)) configurations of helium-like ions with Z = 10−36. Wavelengths, transition rates, oscillator strengths, and line strengths are calculated for the E1, M1, E2, and M2 transitions among these levels. The radiative lifetimes are reported for all the calculated levels. Conclusions. Our MBPT results for singly excited n ≤ 2 levels show excellent agreement with other elaborate calculations, while those for singly excited n ≥ 3 and doubly excited levels show significant improvements over previous theoretical results. Our results will be very helpful for astrophysical line identification and plasma diagnostics.

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Section: Energy Levelsmentioning

confidence: 99%

Energy levels and transition rates for helium-like ions withZ = 10–36

Guo

Wang

et al. 2016

A&A

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“…and 0.3 s.e. for the y-and x-lines, respectively [9]. All lie higher than the predictions of theory.…”

Section: Inconsistency With the Null Hypothesismentioning

confidence: 67%

X-ray measurements in helium-like atoms increased discrepancy between experiment and theoretical QED

et al. 2014

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p ) found a major discrepancy with quantum electrodynamics (QED) and independent nuclear size determinations. Here we find a significant discrepancy in a different type of exotic atom: a medium-Z nucleus with two electrons. Investigation of the data collected is able to discriminate between available QED formulations and reveals a pattern of discrepancy of almost six standard errors of experimental results from the most recent theoretical predictions, with a functional dependence proportional to Z n where ≃ n 4. In both the muonic and highly charged systems, the sign of the discrepancy is the same, with the measured transition energy higher than predicted. Some consequences are possible or probable, and some are more speculative. This may give insight into effective nuclear radii, the Rydberg, the fine-structure constant, or unexpectedly large QED terms.

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“…Furthermore, we would like to emphasize that this apparatus can also be applied for precision spectroscopy of heaviest helium-like ions (as well as other few-electron systems) which, taking into account the unprecedented resolution, would allow for resolving all the relevant fine structure levels for the first time. This is especially interesting in the light of the recent controversy with the comparison between the experimental and theoretical results for helium-like ions [47][48][49][50][51][52][53][54]. Beyer et al 1995 [44] 202.3(7.9) Kraft-Bermuth et al 2016 [30] 211(42) Theory, Yerokhin and Shabaev 2015 [9] 205.2 (2)…”

Section: Discussionmentioning

confidence: 99%

Wavelength-dispersive spectroscopy in the hard x-ray regime of a heavy highly-charged ion: the 1s Lamb shift in hydrogen-like gold

et al. 2018

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Accurate spectroscopy of highly-charged high-Z ions in a storage ring is demonstrated to be feasible by the use of specially adapted crystal optics. The method has been applied for the measurement of the 1s Lamb shift in hydrogen-like gold (Au +78 ) in a storage ring through spectroscopy of the Lyman x-rays. This measurement represents the first result obtained for a high-Z element using high-resolution wavelength-dispersive spectroscopy in the hard x-ray regime, paving the way for sensitivity to higherorder QED effects.

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Helium-like titanium x-ray spectrum as a probe of QED computation

Cited by 20 publications

References 36 publications

Energy levels and transition rates for helium-like ions withZ = 10–36

Energy levels and transition rates for helium-like ions withZ = 10–36

X-ray measurements in helium-like atoms increased discrepancy between experiment and theoretical QED

Wavelength-dispersive spectroscopy in the hard x-ray regime of a heavy highly-charged ion: the 1s Lamb shift in hydrogen-like gold

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