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S. G. Karshenboim

Publications and source records attributed to S. G. Karshenboim.

At least 19 recordsLinked to original sources
arXiv2017

Extraction of the electron mass from $g$ factor measurements on light hydrogenlike ions

The determination of the electron mass from Penning-trap measurements with $^{12}$C$^{5+}$ ions and from theoretical results for the bound-electron $g$ factor is described in detail. Some recently calculated contributions slightly shift the extracted mass value. Prospects of a further improvement of the electron mass are discussed both from the experimental and from the theoretical point of view. Measurements with $^4$He$^+$ ions will enable a consistency check of the electron mass value, and in future an improvement of the $^4$He nuclear mass and a determination of the fine-structure constant.

physics.atom-ph↗
arXiv2011

Comment on "Two-photon approximation in the theory of electron recombination in hydrogen" (D. Solovyev and L. Labzowsky, Phys. Rev. A 81, 062509 (2010))

The results for the total multi-photon decay rates of the 3p and 4s levels of hydrogen, presented by D. Solovyev and L. Labzowsky within the cascade approximation, are revisited. The corrected results for certain decay channels differ from original ones of those authors sometimes by order of magnitude. Some aspects with respect to the cosmological recombination process are clarified.

physics.atom-ph↗
arXiv2010

Non-relativistic contributions in order $α^5m_μc^2$ to the Lamb shift in muonic hydrogen, deuterium and helium ion

Contributions to the energy levels in light muonic atoms and, in particular, to the Lamb shift fall into a few well-distinguished classes. The related diagrams are calculated using different approaches. In particular, there is a specific kind of non-relativistic contributions. Here we consider such corrections to the Lamb shift in order $α^5m_μ$. These contributions are due to free vacuum polarization loops as well as to various effects of light-by-light scattering. The closed loop in the related diagrams is an electronic one, which allows a non-relativistic consideration of the muon. Both kinds of contributions have been known for a while, however, the results obtained up to date are only partial ones. We complete a calculation of the $α^5m_μ$ contributions for muonic hydrogen. The results are also adjusted for muonic deuterium and muonic helium ion.

physics.atom-ph↗
arXiv2010

HFS interval of the $2s$ state of hydrogen-like atoms and a constraint on a pseudovector boson with mass below $1\;$keV$/c^2$

A constraint on a long-range spin-dependent interaction $α^{\prime\prime}({\bf s}_1\cdot{\bf s}_2)\,{\rm e}^{-λr}/r$, which can be induced by a pseudovector light boson, is presented. We study theoretical and experimental data on a specific difference $8\times E_{\rm hfs}(2s)-E_{\rm hfs}(1s)$ for light two-body atoms. The spin-dependent coupling constant $α^{\prime\prime}$ of electron-nucleus interaction in hydrogen, deuterium and helium-3 ion is constrained at the level below a part in $10^{16}$. The derived constraints are related to the range of masses below $4\;{\rm keV}/c^2$.

hep-ph↗
arXiv2010

Constraints on a long-range spin-independent interaction from precision atomic physics

Constraints on a spin-independent interaction by exchange of a neutral light boson are derived from precision data on the electron anomalous magnetic moment and from atomic spectroscopy of hydrogen and deuterium atoms. The mass range from $1 $eV$/c^2$ to $1 $Mev$/c^2$ is studied and the effective coupling constant $α^\prime$ is allowed below the level of $10^{-11} - 10^{-13}$ depending on the value of the boson mass. The mass range corresponds to the Yukawa radius from 0.0002 nm to 20 nm, which covers the distances far above and far below the Bohr radius of the hydrogen atom.

hep-ph↗
arXiv2010

Constraints on a long-range spin-dependent interaction from precision atomic physics

We present a phenomenological constraint on a pseudovector light boson beyond the Standard Model, which can induce a long-range spin-dependent interaction $α^{\prime\prime}({\bf s}_1\cdot{\bf s}_2)\,{\rm e}^{-λr}/r$. In the range of masses from $4\;{\rm keV}/c^2$ to those related to macroscopic distances (of $λ^{-1}\sim1\;$cm) the spin-dependent coupling constant $α^{\prime\prime}$ of the electron-muon interaction is constrained at the level below a part in $10^{15}$. The constraint is weakened while extending to higher masses. The strongest constraint is related to the lepton-lepton interaction. Constraints on spin-dependent interactions of some other particles are also discussed. The results are obtained from data on the HFS interval of the ground state in muonium and a few other light hydrogen-like atoms.

hep-ph↗
arXiv2010

Contribution of Light-by-Light Scattering to Energy Levels of Light Muonic Atoms

The complete contribution of diagrams with the light-by-light scattering to the Lamb shift is found for muonic hydrogen, deuterium and helium ion. The results are obtained in the static muon approximation and a part of the paper is devoted to the verification of this approximation and analysis of its uncertainty.

physics.atom-ph↗
arXiv2010

Precision physics of simple atoms and constraints on a light boson with ultraweak coupling

Constraint on spin-dependent and spin-independent Yukawa potential at atomic scale is developed. That covers constraints on a coupling constant of an additional photon $γ^*$ and a pseudovector boson. The mass range considered is from $1\;{\rm eV}/c^2$ to $1\;{\rm MeV}/c^2$. The strongest constraint on a coupling constant $α^\prime$ is at the level of a few parts in $10^{13}$ (for $γ^*$) and below one part in $10^{16}$ (for a pseudovector) corresponding to mass below $1\;{\rm keV}/c^2$. The constraints are derived from low-energy tests of quantum electrodynamics and are based on spectroscopic data on light hydrogen-like atoms and experiments with magnetic moments of leptons and light nuclei.

hep-ph↗
arXiv2009

New Measurement of the 2S Hyperfine Interval in Atomic Hydrogen

An optical measurement of the 2S hyperfine interval in atomic hydrogen using two-photon spectroscopy of the 1S-2S transition gives a value of 177 556 834.3(6.7) Hz. The uncertainty is 2.4 times smaller than achieved by our group in 2003 and more than 4 times smaller than for any independent radio-frequency measurement. The specific combination of the 2S and 1S hyperfine intervals predicted by QED theory $D_{21}=8 f_{\rm HFS}({2S}) - f_{\rm HFS}({1S})=48 953(3)$ Hz is in good agreement with the value of 48 923(54) Hz obtained from this experiment.

physics.atom-ph↗
arXiv2008

Hadronic Light-by-Light Scattering in the Muonium Hyperfine Splitting

We consider an impact of hadronic light-by-light scattering on the muonium hyperfine structure. A shift of the hyperfine interval $Δν({\rm Mu}) _{\rm\tiny HLBL}$ is calculated with the light-by-light scattering approximated by exchange of pseudoscalar and pseudovector mesons. Constraints from the operator product expansion in QCD are used to fix parameters of the model similar to the one used earlier for the hadronic light-by-light scattering in calculations of the muon anomalous magnetic moment. The pseudovector exchange is dominant in the resulting shift, $Δν({\rm Mu})_{\rm\tiny HLBL}= -0.0065(10) {Hz}$. Although the effect is tiny it is useful in understanding the level of hadronic uncertainties.

hep-ph↗
arXiv2008

Electron shielding of the nuclear magnetic moment in hydrogen-like atom

The correction to the wave function of the ground state in a hydrogen-like atom due to an external homogenous magnetic field is found exactly in the parameter $Zα$. The $j=1/2$ projection of the correction to the wave function of the $ns_{1/2}$ state due to the external homogeneous magnetic field is found for arbitrary $n$. The $j=3/2$ projection of the correction to the wave function of the $ns_{1/2}$ state due to the nuclear magnetic moment is also found for arbitrary $n$. Using these results, we have calculated the shielding of the nuclear magnetic moment by the $ns_{1/2}$ electron.

physics.atom-ph↗
arXiv2007

The Uehling correction in muonic atoms exactly in Zα

The Uehling correction to the energy levels is presented in terms of the hypergeometric functions 2F1. This presentation allows to derived various asymptotics and approximations. Further applications of this method to other atomic characteristics are also considered.

physics.atom-ph↗
arXiv2006

Study of hyperfine structure in simple atoms and precision tests of the bound state QED

We consider the most accurate tests of bound state QED, precision theory of simple atoms, related to the hyperfine splitting in light hydrogen-like atoms. We discuss the HFS interval of the 1s state in muonium and positronium and of the 2s state in hydrogen, deuterium and helium-3 ion. We summarize their QED theory and pay attention to involved effects of strong interactions. We also consider recent optical measurements of the 2s HFS interval in hydrogen and deuterium.

hep-ph↗
arXiv2006

Vacuum polarization in muonic and antiprotonic atoms: the fine structure at medium Z

Effects of vacuum polarization modify the energy levels in atoms with an orbiting particle heavier than an electron. The dominant effect is due to the Uehling potential. In this paper we consider the relativistic corrections to the energy levels caused by the Uehling potential and in particular the fine structure in muonic and antiprotonic atoms. We derive general expressions and consider in detail specific regions of parameters which allow simple asymptotic expansion. We take into account the recoil effects and anomalous magnetic moment in the case of an antiproton as the orbiting particle.

physics.atom-ph↗
arXiv2006

The Uehling correction to the energy levels in a pionic atom

We consider a correction to energy levels in a pionic atom induced by the Uehling potential, i.e., by a free electron vacuum-polarization loop. The calculation is performed for circular states (l=n-1). The result is obtained in a closed analytic form as a function of $ Zα$ and the pion-to-electron mass ratio. Certain asymptotics of the result are also presented.

physics.atom-ph↗
arXiv2005

A New Option for a Search for Alpha Variation: Narrow Transitions with Enhanced Sensitivity

We consider several transitions between narrow lines that have an enhanced sensitivity to a possible variation of the fine structure constant, alpha. This enhancement may allow a search to be performed with an effective suppression of the systematic sources of uncertainty that are unavoidable in conventional high-resolution spectroscopic measurements. In the future this may provide the strongest laboratory constraints on alpha variation.

physics.atom-ph↗