Precise measurement of the Lamb shift and fine structure of the 2<i>S</i>-2<i>P</i>transition in triplet helium

Shiner, David; Dixson, Ronald G.; Zhao, Ping

doi:10.1103/physrevlett.72.1802

Cited by 70 publications

(53 citation statements)

References 28 publications

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“…Precise frequency measurements of larger energy intervals, like 2 3 S→2 3 P (Cancio Pastor et al, 2004Shiner et al, 1994) provide a unique opportunity to test two-electron Lamb shift calculations, which, of course, are absent in one-electron atoms. The most precise Lamb-shift contribution to a transition frequency in a simple atomic system, including hydrogen and deuterium, was determined by the optical frequency comb assisted frequency measurements of the 1083 nm 4 He transitions (Cancio Pastor et al, 2004.…”

Section: Spectroscopic Measurements Of Atomic Properties a Metasmentioning

confidence: 99%

Cold and trapped metastable noble gases

et al. 2012

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We review experimental work on cold, trapped metastable noble gases. We emphasize the aspects which distinguish work with these atoms from the large body of work on cold, trapped atoms in general. These aspects include detection techniques and collision processes unique to metastable atoms. We describe several experiments exploiting these unique features in fields including atom optics and statistical physics. We also discuss precision measurements on these atoms including fine structure splittings, isotope shifts, and atomic lifetimes.

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Section: Spectroscopic Measurements Of Atomic Properties a Metasmentioning

confidence: 99%

Cold and trapped metastable noble gases

et al. 2012

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“…This is expected to result in a theoretical value for the larger, approximately 29.6 GHz, J 0 1 interval in helium to better than 61 kHz. Combined with measurements aimed at exceeding this precision [6][7][8][9], this should yield a value for a at the 16 ppb (parts per 10 9 ) level. This would be of interest for comparison with the result obtained from QED theory and experiment for the electron magnetic moment, and with results obtained from the various other phenomena reviewed in Ref.…”

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confidence: 99%

Precision Measurement of the1s2pP32
Myers
¹
,
Margolis
²
,
Thompson
³

et al. 1999
Phys. Rev. Lett.
44
2
11
0
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Using Doppler-tuned fast-beam laser spectroscopy with co-and counterpropagating beams we have measured the three hyperfine components of the 1s2p 3 P 2 -3 P 1 fine structure interval in 19 F 71 . Our result for the centroid is 957.6679͑10͒ cm 21 . Allowing for the hyperfine interaction the "pure" fine structure interval is determined to be 957.8730͑12͒ cm 21 . This result tests O͑a 7 m e c 2 ͒ quantum electrodynamic corrections to high precision calculations which will be used to obtain a new value for the fine structure constant from the fine structure of helium. [S0031-9007 (99)09157-7] PACS numbers: 32.10.Fn, 06.20.JrThe fine structure constant, a, is the fundamental constant which expresses the elementary charge in dimensionless form and hence plays a crucial role in unifying an enormous range of physical phenomena [1]. There is now a program to obtain a new value for a from comparison of theory and experiment for the 1s2p 3 P J2J 0 fine structure of atomic helium. Drake and co-workers, using matrix elements of operators derived from the Bethe-Salpeter equation, evaluated with high-precision nonrelativistic wave functions, aim to complete calculations to order a 5 a.u. (or a 7 m e c 2 ) [2-4]. Independent calculations of the effective operators are also being carried out by Pachucki [5]. This is expected to result in a theoretical value for the larger, approximately 29.6 GHz, J 0 1 interval in helium to better than 61 kHz. Combined with measurements aimed at exceeding this precision [6-9], this should yield a value for a at the 16 ppb (parts per 10 9 ) level. This would be of interest for comparison with the result obtained from QED theory and experiment for the electron magnetic moment, and with results obtained from the various other phenomena reviewed in Ref. [1].Compared to other methods dependent on QED theory for obtaining a, helium fine structure has an advantage in that the theory, in particular, the evaluation of the complex higher-order relativistic and QED corrections, FIG. 1. Schematic of the experimental arrangement. G is a diffraction grating, W is a window, L is a lens, M1, M2 are mirrors, EM1, EM2 are electromagnets, PM is a permanent magnet, and PC is a proportional counter.can be independently tested. This is because there are two 2 3 P fine structure intervals and because the same methods used for helium can be used to calculate fine structure in moderate Z heliumlike ions where the relative magnitudes of these higher-order terms are larger. Hence fine structure measurements in moderate Z heliumlike ions [10-15], even though less precise than measurements in helium, can provide sensitive tests of the theory. Here we report a measurement of the three hyperfine components of the 19 F 71 1s2p 3 P 2 -3 P 1 fine structure interval, obtained by directly inducing the M1 transitions using a CO 2 laser, in a fast, foil stripped fluorine ion beam. A novel Doppler shift cancellation technique was used which measures products of the transition energies in pairs. Our result, with a precision of 61 ppm ...

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“…The LXR subfamily of nuclear receptors contains two members, LXRa (NR1H3) [15] and LXRb (NR1H2) [16][17][18][19]. LXRa and b share the canonical nuclear receptor structure [15,20], and LXR/RXR heterodimers bind to response elements (LXREs) containing the hexameric sequence (AGGTCA) separated by four nucleotides (DR4 element) [15,16,[20][21][22].…”

Section: Lxr Activationmentioning

confidence: 99%

Liver X receptors in cardiovascular and metabolic disease

Geyeregger

Zeyda

Stulnig

2006

Cell. Mol. Life Sci.

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Liver X receptors (LXRs) alpha and beta are nuclear oxysterol receptors and metabolic sensors initially found to regulate cholesterol metabolism and lipid biosynthesis. Recent studies have elucidated the importance of LXR in the development of cardiovascular diseases and metabolic disorders. LXR agonists prevent development of atherosclerosis by modulation of metabolic as well as inflammatory gene expression in rodent models. Moreover, LXR activation inhibits hepatic gluconeogenesis and lowers serum glucose levels, indicating possible application of LXR activation in the treatment of diabetes mellitus. However, first-generation LXR agonists elevate hepatic and serum trigylceride levels, making subtype-specific agonists and selective LXR modulators rather than unselective LXR agonists a potential pharmacological strategy. This review summarizes the multiple physiological and pathophysiological implications of LXRs and observations that identify LXRs as potential targets for therapeutic interventions in human cardiovascular and metabolic disease.

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Precise measurement of the Lamb shift and fine structure of the 2S-2Ptransition in triplet helium

Cited by 70 publications

References 28 publications

Cold and trapped metastable noble gases

Cold and trapped metastable noble gases

Precision Measurement of the1s2pP32
Myers
¹
,
Margolis
²
,
Thompson
³

et al. 1999
Phys. Rev. Lett.
44
2
11
0
View full text Add to dashboard Cite

Liver X receptors in cardiovascular and metabolic disease

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Precise measurement of the Lamb shift and fine structure of the 2S-2Ptransition in triplet helium

Cited by 70 publications

References 28 publications

Cold and trapped metastable noble gases

Cold and trapped metastable noble gases

Precision Measurement of the1s2pP32Myers1, Margolis2, Thompson3 et al. 1999Phys. Rev. Lett.442110View full textAdd to dashboardCite

Liver X receptors in cardiovascular and metabolic disease

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Precision Measurement of the1s2pP32
Myers
¹
,
Margolis
²
,
Thompson
³

et al. 1999
Phys. Rev. Lett.
44
2
11
0
View full text Add to dashboard Cite