bluuebunny/crossref_metadata_2025_split huggingface dataset:
Testing of QED theory on the Rydberg series for the He-like multicharged ions
Authors: Pal'chikov V G , Skobelev I Yu. , Faenov A Ya. 
Published: December 2002

The paper examines the 1/Z expansion method in calculating the energy levels, ionization energies, and wavelengths of the resonant Rydberg states 1snp 1P1 for atoms belonging to the helium isoelectronic sequence. The interactions of the bound electrons are treated as a perturbation that results in the electronelectron Breit interaction, relativistic corrections, and quantum electrodynamic (QED) contributions. By comparing the calculated wavelengths with a number of observed wavelengths, the QED contributions to the ground state are analyzed. PACS Nos.: 31.20Di, 31.20Tz, 31.30Jv, 31.50+W
Systematic model calculations of the hyperfine structure in light and heavy ions
Authors: Tomaselli M , Kühl Th. , Nörtershäuser W , Ewald G , Sanchez R , Fritzsche S , Karshenboim S G 
Published: December 2002

Systematic model calculations are performed for the magnetization distributions and the hyperfine structure (HFS) of light and heavy ions with a mass close to A ~ 6 208 235 to test the interplay of nuclear and atomic structure. A high-precision measurement of lithium-isotope shifts (IS) for suitable transition, combined with an accurate theoretical evaluation of the mass-shift contribution in the respective transition, can be used to determine the root-mean-square (rms) nuclear-charge radius of Li isotopes, particularly of the halo nucleus 11Li. An experiment of this type is currently underway at GSI in Darmstadt and ISOLDE at CERN. However, the field-shift contributions between the different isotopes can be evaluated using the results obtained for the charge radii, thus casting, with knowledge of the ratio of the HFS constants to the magnetic moments, new light on the IS theory. For heavy charged ions the calculated n-body magnetization distributions reproduce the HFS of hydrogen-like ions well if QED contributions are suppressed. Ab-initio calculations of the HFS of 209Bi80+ were performed to analyse this surprising result. Here, the boiling of the QED vacuum gives an important contribution to the HFS, thus modifying the theoretical results of other models. The investigations performed have initiated detailed studies of the structure of lithium-like ions heavier then bismuth, to obtain predictions for the experiments on uranium, which are proposed at PHELIX-XRL. PACS Nos.: 31.15Pf, 31.30Jv, 32.10Hq, 21.10GV, 21.10FT, 21.60-n, 21.60+n
VNIIFTRI cesium fountain
Authors: Domnin Yu. S , Elkin G A , Novoselov A V , Kopylov L N , Baryshev V N , Pal'chikov V G 
Published: December 2002

The state of affairs with the development of the Russian cesium fountain is presented. Design of the physical parts, the laser system, and the optical system is briefly outlined. The preliminary results of the operation with a magnetic-optical trap (MOT) and molasses are described. Temperatures of about 20 µ K for MOT and 10 µ K for molasses are reached. PACS Nos.: 06.30Ft, 32.80Pj, 42.50Vk
Nonresonant corrections for the hydrogen atom
Authors: Labzowsky L N , Solovyev D A , Plunien G , Soff G 
Published: December 2002

The nonresonant (NR) corrections are estimated for the 1s2p one-photon and for the 1s2s two-photon resonances in the hydrogen atom. These corrections depend on the measurement process and set the limit for the accuracy of atomic frequency measurements. With the measurement process accepted in recent experiments the NR contribution for the 1s2s transition energy can reach 103 Hz while the experimental inaccuracy is quoted to be ±46 Hz. PACS Nos.: 31.30Jv, 12.20Ds, 06.20Jr, 31.15-p
Search for an exotic three-body decay of orthopositronium o-Ps   γ + X1 + X2
Authors: Crivelli P 
Published: December 2002

We carried out a model independent search for an exotic three-body decay of orthopositronium o-Ps [Formula: see text] γ + X1 + X2 into a photon and two weak interacting particles X1 and X2. The existence of this decay could explain the discrepancy between the measured and the predicted values of the orthopositronium-decay rate in vacuum. Our result excludes this decay mode as the origin of the discrepancy and an upper limit on the branching ratio has been set B(o-Ps [Formula: see text] γ + X1 + X2) < 4.4 x 105 (at the 90% confidence level), for the photon energy in the range from 40 < Eγ < 400 keV and for the weak interacting particles X mass range 0 [Formula: see text] mX1 + mX2 [Formula: see text] 900 keV. PACS No.: 36.10Dr
Measurement of the gJ factor of a bound electron in hydrogen-like oxygen 16O7+
Authors: Verdú J L , Beier T , Djekic S , Häffner H , Kluge H -J , Quint W , Valenzuela T , Werth G 
Published: December 2002

The magnetic moment of the electron bound in hydrogen-like oxygen O7+ has been determined using the "continuous SternGerlach effect" in a double Penning trap. We obtained a relative precision of 2 x 109. This tests calculations of bound-state quantum electrodynamics and nuclear correction. PACS No.: 32.10Dk
Hyperfine quenching of the 23P0,2 states in He-like ions
Authors: Volotka A V , Shabaev V M , Plunien G , Soff G , Yerokhin V A 
Published: December 2002

The transition probabilities of the lines 11 S0  23 P0 and 11 S0  23 P2 in He-like ions with nonzero nuclear spins are calculated. The hyperfine-quenching effect on the lifetimes of the 23 P0,2 states is investigated. The Coulomb and Breit interelectronic interactions are taken into account to the order (α Z)2/Z by means of perturbation theory. The calculation is performed for both length and velocity gauges. The transition rates evaluated are in good agreement with previous 1/Z and CI calculations. PACS No.: 32.70Cs
Development of the new method of positronium generation. Abilities and future trends
Authors: Antropov V , Ivanov A , Korotaev Yu. , Mamedov T , Meshkov I , Seleznev I , Sidorin A , Smirnov A , Syresin E , Trubnikov G , Yakovenko S 
Published: December 2002

Presently the positron ring dedicated to positronium generation and called the Low Energy Positron Toroidal Accumulator (LEPTA) is under construction at JINR (Dubna). The main application of this ring is the generation of a monoenergetic and directed flux of positronium atoms and its use in experiments. Positronium is generated in interactions of positrons, circulating inside a storage ring accumulator, with free electrons of the cooling electron beam that have velocities very close to the positron velocities. This allows us to obtain a high positronium flux with small angular and velocity spreads of the atoms and provides a significant advantage for the proposed arrangement of experiments, so-called positronium-in-flight setups, as compared with traditional approaches in which positronium was generated in targets. In particular, the precision in measuring positronium parameters (lifetime, the probability of decays with momentum conservation, charge invariant violation (CPT violation), fine structure of the positronium spectrum, and Lamb-shift measurements) can be enhanced by several orders of magnitude. Moreover, some experiments that are unrealistic within traditional schemes become feasible with the proposed facility. PACS No.: 36.10Dr
Precise energies of highly excited hydrogen and deuterium
Authors: Kotochigova S , Mohr P J , Taylor B N 
Published: December 2002

The energy levels of hydrogen and deuterium atoms are calculated to provide frequencies for transitions between highly excited states with principal quantum number n up to 200. All known quantum electrodynamics and relativistic corrections have been included in the calculation. In some cases, contributions originally calculated for a few states have been extrapolated to highly excited states. The fundamental constants necessary for the calculation are taken from the 1998 CODATA least-squares adjustment. Evaluated uncertainties take into account uncertainties in the theoretical calculations, uncertainties in the fundamental constants, and covariances between the various contributions and input parameters. PACS Nos.: 31.15Pf, 31.30Jv, 32.10Hq
The diamagnetic effect on the intensity of helium radiation lines
Authors: Ovsiannikov V D , Chernushkin V V 
Published: December 2002

The changes of the radiation matrix elements, probabilities, and line intensities in a strong magnetic field are studied for the helium lines, corresponding to transitions between Zeeman manifolds with |m| [Formula: see text] 3. The effect of a selective field action on radiation lines is discovered that may reduce and enhance corresponding matrix elements and induce the dipole-forbidden transitions with the selection rule |Δl| = 3. PACS Nos.: 32.60+i, 32.70Fw, 32.30-r
The PaschenBack effect in helium spectra revisited
Authors: Ovsiannikov V D , Tchaplyguine E V 
Published: December 2002

The complete information for the intensities of the Zeeman components in the helium triplet lines corresponding to the radiation transitions n3 PJM [Formula: see text] n' 3S1M ' is analyzed in the field-strength region from anomalous Zeeman effects to complete PaschenBack effects. The diagonalization of the paramagnetic interaction for n3PJM was carried out for the states with magnetic quantum number M = 0 in the Hilbert space of dimension 3, taking account of all three fine-structure sublevels, J = 0,1,2. The results of the numerical calculations for line positions and intensities are presented in a table and figures. The departure from the previously known data is discussed. PACS Nos.: 32.60+i, 32.70Fw, 32.30-r
Hadronic effects in leptonic systems: muonium hyperfine structure and anomalous magnetic moment of muon
Authors: Eidelman S I , Karshenboim S G , Shelyuto V A 
Published: December 2002

The contributions of hadronic effects to muonium physics and the anomalous magnetic moment of muon are considered. Special attention is paid to higher order effects and the uncertainty related to the hadronic contribution to the hyperfine-structure interval in the ground state of muonium. PACS Nos.: 12.20-m, 36.10Dr, 31.30Jv, 13.65+i
The g factor in a light two-body atomic system: a determination of fundamental constants to test QED
Authors: Karshenboim S G , Ivanov V G 
Published: December 2002

The energy levels of a two-body atomic system in an external homogeneous magnetic field can be presented in terms of the magnetic moments of their components, however, those magnetic moments being related to bound particles differ from their free values. The study of bound g-factors in simple atomic systems are now of interest because of recent progress in experiments on medium-Z ions and of a new generation of muonium experiments possible with upcoming intensive muon sources. We consider bound corrections to the g factors in several atomic systems, for which experimental data are available in the literature: hydrogen, helium-3 ion, muonium, hydrogen-like ions with spinless nuclei with medium Z. PACS Nos.: 12.20Fv, 31.30Jv, 32.10Hq
The structure of light nuclei and its effect on precise atomicmeasurements
Authors: Friar J L 
Published: December 2002

The paper consists of three parts: (i) what every atomic physicist needs to know about the physics of light nuclei (and no more); (ii) what nuclear physicists can do for atomic physics; and (iii) what atomic physicists can do for nuclear physics. A brief qualitative overview of the nuclear force and calculational techniques for light nuclei will be presented, with an emphasis on debunking myths and on recent progress in the field. Nuclear quantities that affect precise atomic measurements will be discussed, together with their current theoretical and experimental status. The final topic will be a discussion of those atomic measurements that would be useful to nuclear physics. PACS No.: 31.30Gs
Relativistic linear response wave function of the lowest ns 1/2 states in hydrogen-like atoms. New analytic results
Authors: Yakhontov V 
Published: December 2002

A novel closed-form analytic representation for the linear response relativistic wave function of the hydrogenic ns 1/2 level that is exposed to a uniform dipole radiation of frequency ω is reported. This result is derived using a relativistic version of the PodolskySternheimerDalgarnoLewis method, that is, by means of direct analytical solving of the appropriate inhomogeneous ω-dependent Dirac equation, thus requiring no prior knowledge of the relativistic Coulomb Green's function. The utility of the formulas obtained for numerous potential applications is illustrated by new results of analytic and numerical calculations of the relativistic dipole dynamic polarizabilities of the 1s1/2 and 2s1/2 levels in hydrogen-like atoms. PACS Nos.: 31.15Pf, 31.30Jv, 32.10Hq
A detector with high detection efficiency in 4- and 5-photon-positronium annihilations
Authors: Chiba M , Nakagawa J , Tsugawa H , Ogata R , Nishimura T 
Published: December 2002

We first measured 4- and 5-photon annihilations in positronium using a multiphoton spectrometer (UNI), which consists of 32 NaI(Tl) scintillators with lead shields, each being located on a surface of an icosidodecahedron. The front face of each scintillator is placed at a distance of L = 262 mm from the center of the UNI. With this setup, the detection efficiency of 4- and 5-photon-annihilation processes are too small to get a sufficient number of events to analyze the physics. To obtain a larger detection efficiency, we must set the NaI(Tl) scintillators closer to the target. The original principle in designing the UNI was to suppress backgrounds (BG) and make them as low as possible allowing modest efficiencies for 4- and 5-photon-annihilation events, i.e., to get the highest signal-to-noise ratio (S/N). The new concept is to get the highest S/σ where σ is an error of one standard deviation of the signal including BG effects. A higher S/σ means a larger number of events with smaller BG taking into account a statistical effect. The detection efficiencies with BG effects are studied with respect to L using a detector simulator based on the EGS4 code in which 2- to 5-photon-annihilation events are generated by quantum-electrodynamic processes based on GRACE and BASES/SPRING codes. As a result, the detection efficiency and S/σ of 5-photon annihilations at L = 136 mm are 529 and 17 times larger than those at L = 262 mm, respectively. PACS Nos.: 36.10Dr, 12.20Fv, 13.10+q
Single-ion mass spectrometry at 100 ppt and beyond
Authors: Rainville S , Thompson J K , Pritchard D E 
Published: December 2002

Using a Penning trap single-ion mass spectrometer, we measured the atomic masses of 14 isotopes with a fractional accuracy of ~1010. The precision on these measurements was limited by the temporal fluctuations of our magnetic field. By trapping two different ions in the same Penning trap at the same time, we have recently been able to virtually eliminate that source of error. We can now simultaneously measure the ratio of the two ion's cyclotron frequencies (from which we obtain their atomic mass ratio) with a precision of about 1011 in only a few hours. To perform these comparisons, we must be able to measure and control all three normal modes of motion of each ion  cyclotron, axial, and magnetron  and have developed novel techniques to do so. This new technique shows promise of expanding the precision of mass spectrometry by an order of magnitude beyond the current state-of-the-art. PACS Nos.: 32.10Bi, 06.20Jr, 06.30Dr, 07.75+h, 07.77-n
Progress in helium fine-structure calculations and the fine-structure constant
Authors: Drake G WF 
Published: December 2002

The long-term goal of this work is to determine the fine-structure constant α from a comparison between theory and experiment for the fine-structure splittings of the helium 1s2p 3PJ states. All known terms of order α5 a.u. (α7 mc2) arising from the electronelectron interaction, and recoil corrections of order α4 µ / M a.u. are evaluated and added to previous tabulation. The predicted energy splittings are ν0,1 = 29 616.946 42(18) MHz and ν1,2 = 2291.154 62(31) MHz. Although the computational uncertainty is much less than ±1 kHz, there is an unexplained discrepancy between theory and experiment of 19.4(1.4) kHz for ν1,2. PACS Nos.: 31.30Jv, 32.10Fn
Gyromagnetic factors of bound particles with arbitrary spin in quantum electrodynamics
Authors: Faustov R N , Martynenko A P 
Published: December 2002

A quasipotential method is formulated for calculating relativistic and radiative corrections to the magnetic moment of a two-particle bound state in the case of particles with arbitrary spin. It is shown that the g factors of bound particles contain O(α2) terms depending on the particle spin. Numerical values for the g factors of the electron in the hydrogen atom and deuterium are obtained. PACS Nos.: 31.30Jv, 12.20Ds, 32.10Dk
Gross Variability in the Detection of Prolactin in Sera Containing Big Big Prolactin (Macroprolactin) by Commercial Immunoassays
Authors: Smith Thomas P. , Suliman Abdulwahab M. , Fahie-Wilson Michael N. , McKenna T. Joseph 
Published: December 2002

Abstract
A high molecular mass form of prolactin (PRL), macroprolactin, accumulates in the sera of some subjects. Although macroprolactin exhibits limited bioactivity in vivo, it retains immunoreactivity. We examined the frequency of macroprolactinemia in clinical practice and the ability of immunoassay systems to distinguish between macroprolactin and monomeric PRL. Of 300 hyperprolactinemic sera identified, 71 normalized following treatment of sera with polyethylene glycol, indicating that 24% of hyperprolactinemia could be accounted for by macroprolactin. Ten of these macroprolactinemic sera were circulated to 18 clinical laboratories. Two sets of PRL measurements of the 10 untreated sera were obtained from each of the nine most commonly used immunoassay systems. Across the nine assay systems, differences in the PRL estimates ranged from 2.3- to 7.8-fold. Elecsys users reported the highest PRL levels. Somewhat lower values were reported for DELFIA systems followed by Immuno-1, AxSYM, and Architect assays. The Immulite 2000 assay generated PRL levels equivalent to approximately 50% of those reported by the high-reading methods. The lowest PRL levels were reported by Access, ACS:180, and Centaur systems. To avoid confusion caused by the frequent presence of macroprolactin accounting for hyperprolactinemia, secondary screening for the presence of macroprolactin is recommended.
Estradiol and Interleukin-1β Exert a Synergistic Stimulatory Effect on the Expression of the Chemokine Regulated upon Activation, Normal T Cell Expressed, and Secreted in Endometriotic Cells
Authors: Akoum Ali , Lemay André , Maheux Rodolphe 
Published: December 2002

AbstractEndometriosis, commonly associated with intraperitoneal inflammation, is estrogen dependent. Possible links between the immunoinflammatory and endocrine changes observed in endometriotic women have been poorly understood. In this study, we report that estradiol (E2) and IL-1β exert a synergistic stimulatory action on RANTES (regulated upon activation, normal T cell expressed, and secreted) expression by endometriotic cells. Treatment of endometriotic cells with IL-1β had a dose-dependent effect on RANTES protein secretion and mRNA steady state levels, whereas cell treatment with E2 or progesterone had no detectable effect. Interestingly, treatment of endometriotic cells with E2 before stimulation with IL-1β resulted in a further increase in RANTES protein secretion and mRNA steady state levels, compared with IL-1β alone, whereas treatment with progesterone did not significantly affect cell responsiveness to IL-1β. Assessment of RANTES mRNA half-life revealed that cell pretreatment with E2 enhanced RANTES mRNA stability and increased gene transcription as shown by run-on analysis. Immunohistochemical analysis of RANTES in endometriotic tissue showed immunostaining to be predominant in the stroma with no noticeable differences in tissues from the proliferative and secretory phase of the menstrual cycle. This appears to be consistent with the cell culture data and indicates that RANTES expression in endometriotic tissue is not subject to cyclic variation. These findings reveal a new regulatory mechanism by which IL-1β produced by activated macrophages can in synergy with ovarian and locally produced E2 lead to enhanced macrophage and T-lymphocyte recruitment, thereby exacerbating the local immunoinflammatory process. Furthermore, the findings provide a further evidence for a close relationship between the endocrine and immunological changes observed in endometriosis.
Neurosurgical Treatment of Nelson’s Syndrome
Authors: Kelly P. A. , Samandouras G. , Grossman A. B. , Afshar F. , Besser G. M. , Jenkins P. J. 
Published: December 2002

Abstract
Total bilateral adrenalectomy remains the definitive procedure for cure in Cushing’s disease. It is complicated by the development of Nelson’s syndrome, the treatment of which remains troublesome. We report the long-term follow-up, median 17 yr (range, 8–22 yr), of 13 patients (3 males and 10 females) treated with pituitary surgery for Nelson’s syndrome at a median age of 35 yr (range, 21–67 yr). The presence of a pituitary mass lesion necessitated neurosurgery in all. Preoperatively, the median plasma ACTH level was 664 pmol/liter (range, 92–3665 pmol/liter); this fell to 29 pmol/liter (range, &lt;2 to 1124 pmol/liter) postoperatively (P &lt; 0.0005). Cutaneous hyperpigmentation was reduced in all and resolved in 11 patients. The pituitary tumor bulk was clearly reduced in 12 patients. There was no perioperative mortality. No patient developed a visual field defect attributable to surgery. New anterior pituitary hormone deficiency occurred in seven patients, and permanent diabetes insipidus occurred in five patients. At latest follow-up, the median plasma ACTH is 73 pmol/liter (range, &lt;2 to 7759 pmol/liter); six patients have levels of less than 44 pmol/liter and also have a resolution of their pigmentation and no evidence of a recurrence of a pituitary mass lesion. We conclude that pituitary surgery is an efficacious treatment for mass lesions associated with Nelson’s syndrome, has long-term benefit with minimal side effects, and must be considered in the management of this distressing complication.