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Savely G. Karshenboim

Publications and source records attributed to Savely G. Karshenboim.

At least 37 records · Page 2Linked to original sources
arXiv2008

K0 meson physics in the gravitation field: a constraint on the equivalence principle

K0-K0bar oscillations are extremely sensitive to the K0 and K0bar energy at rest. Even assuming m_K0=m_K0bar, the energy is not granted to be the same if gravitational effects on K0 and K0bar slightly differ. We consider various gravitation fields present and, in particular, galactic fields, which provide a negligible acceleration, but relatively large gravitational potential energy. A constraint from a possible effect of this potential energy on the kaon oscillations isfound to be |(m_g/m_i)_K0-(m_g/m_i)_K0bar| < 8 x 10^-13 atCL=90%. The derived constraint is competitive with other tests of universality of the free fall. Other applications are also discussed.

gr-qc↗
arXiv2008

A constraint on antigravity of antimatter from precision spectroscopy of simple atoms

Consideration of antigravity for antiparticles is an attractive target for various experimental projects. There are a number of theoretical arguments against it but it is not quite clear what kind of experimental data and theoretical suggestions are involved. In this paper we present straightforward arguments against a possibility of antigravity based on a few simple theoretical suggestions and some experimental data. The data are: astrophysical data on rotation of the Solar System in respect to the center of our galaxy and precision spectroscopy data on hydrogen and positronium. The theoretical suggestions for the case of absence of the gravitational field are: equality of electron and positron mass and equality of proton and positron charge. We also assume that QED is correct at the level of accuracy where it is clearly confirmed experimentally.

gr-qc↗
arXiv2007

Positronium-ion decay

We present a precise theoretical prediction for the decay width of the bound state of two electrons and a positron (a negative positronium ion), Gamma(Ps^-) = 2.087 085(12)/ns. We include O(alpha^2) effects of hard virtual photons as well as soft corrections to the wave function and the decay amplitude. An outcome of a large-scale variational calculation, this is the first result for second-order corrections to a decay of a three-particle bound state. It will be tested experimentally in the new positronium-ion facility in Garching in Germany.

hep-ph↗
arXiv2006

Sum rules for an atomic hyperfine structure in a magnetic field

Sum rules for the energy levels of a hyperfine multiplet in a constant uniform magnetic field is presented. It is found that for any values of the electron angular moment and the nuclear spin there are certain linear combinations of energy levels which do not depend on the magnetic field and can be used to determine the unperturbated hfs separation in the presence of perturbing magnetic field. It is also demonstrated that there are other linear combinations which are linear with the external magnetic field and hence can be used to determine bound values of the electron and nuclear magnetic moments. The accuracy of the approximation within which the result is valid is also discussed.

physics.atom-ph↗
arXiv2006

Vacuum polarization in muonic atoms: the Lamb shift at low and medium Z

In muonic atoms the Uehling potential (an effect of a free electronic vacuum polarization loop) is responsible for the leading contribution to the Lamb shift causing the splitting of states with Delta n = 0 and Delta l \neq 0. Here we consider the Lamb shift in the leading nonrelativistic approximation, i.e., within an approach based on a certain Schrodinger equation. That is valid for low and medium $Z$ as long as (Z alpha)^2 >> 1. The result is a function of a few parameters, including kappa = Z alpha m_ mu/m_e, n and l. We present various asymptotics and in particular we study a region of validity of asymptotics with large and small kappa. Special attention is paid to circular states, which are considered in a limit of n >> 1.

physics.atom-ph↗
arXiv2005

Precision physics of simple atoms: QED tests, nuclear structure and fundamental constants

Quantum electrodynamics is the first successful and still the most successful quantum field theory. Simple atoms, being essentially QED systems, allow highly accurate theoretical predictions. Because of their simple spectra, such atoms have been also efficiently studied experimentally frequently offering the most precisely measured quantities. Our review is devoted to comparison of theory and experiment in the field of precision physics of light simple atoms. In particular, we consider the Lamb shift in the hydrogen atom, the hyperfine structure in hydrogen, deuterium, helium-3 ion, muonium and positronium, as well as a number of other transitions in positronium. Additionally to a spectrum of unperturbed atoms, we consider annihilation decay of positronium and the g factor of bound particles in various two-body atoms. Special attention is paid to the uncertainty of the QED calculations due to the uncalculated higher-order corrections and effects of the nuclear structure. We also discuss applications of simple atoms to determination of several fundamental constants.

hep-ph↗
arXiv2005

On a natural definition of the kilogram and the ampere: the objectives and consequences

We consider a recent proposal [1] to redefine the kilogram in terms of natural constants. In our opinion, the main objective of the redefinition should be to build such a version of the SI system in which the electric measurements are possible with the highest accuracy in SI units, and not in practical units as now. We emphasize that this objective can be achieved only with a simultaneous redefinition of the kilogram and ampere. This redefinition must be in terms of fixed values of the Planck constant h and the elementary charge e. Certain details of the possible redefinition are considered.

physics.class-ph↗
arXiv2005

Fundamental Physical Constants: Looking from Different Angles

We consider fundamental physical constants which are among a few of the most important pieces of information we have learned about Nature after its intensive centuries-long studies. We discuss their multifunctional role in modern physics including problems related to the art of measurement, natural and practical units, origin of the constants, their possible calculability and variability etc.

physics.atom-ph↗
arXiv2005

Improved theoretical prediction for the 2s hyperfine interval in helium ion

We consider the uncertainty of theoretical calculations for a specific difference of the hyperfine intervals in the 1s and 2s states in a light hydrogen-like atom. For a number of crucial radiative corrections the result for hydrogen atom and helium ion appears as an extrapolation of the numerical data from medium to low Z. An approach to a plausible estimation of the uncertainty is suggested using the example of the difference $D_{21}= 8E_{hfs}(2s)-E_{hfs}(1s)$.

hep-ph↗
arXiv2004

Atomic Clocks and Constraints on Variations of Fundamental Constants

We consider an application of precision frequency measurements to searches for possible time variations of the fundamental physical constants. Current laboratory constraints on variations of the fine structure constant alpha and other fundamental constants are presented.

physics.atom-ph↗
arXiv2003

Search for Possible Variation of the Fine Structure Constant

Determination of the fine structure constant alpha and search for its possible variation are considered. We focus on a role of the fine structure constant in modern physics and discuss precision tests of quantum electrodynamics. Different methods of a search for possible variations of fundamental constants are compared and those related to optical measurements are considered in detail.

physics.atom-ph↗
arXiv2003

Precision Study of Positronium: Testing Bound State QED Theory

As an unstable light pure leptonic system, positronium is a very specific probe atom to test bound state QED. In contrast to ordinary QED for free leptons, the bound state QED theory is not so well understood and bound state approaches deserve highly accurate tests. We present a brief overview of precision studies of positronium paying special attention to uncertainties of theory as well as comparison of theory and experiment. We also consider in detail advantages and disadvantages of positronium tests compared to other QED experiments.

hep-ph↗
arXiv2003

NMR spectroscopy of hydrogen deuteride and magnetic moments of deuteron and triton

Magnetic moments of free and bound deuteron and triton are considered and new results for their magnetic moments (in units of that of the proton) and their g factors are presented. We report on a measurement with medium-pressure hydrogen deuteride (HD) at 10 atm, which is to be compared with the previous measurement done at 100 atm. We confirm that the high pressure used in former experiments caused no systematic effects at a level of 10 ppb. We also reexamined a theoretical uncertainty related to screening effects in HD and HT molecules and found that previously it was underestimated. The medium-pressure result obtained for the free deuteron mu_d/mu_p=0.307 012 206 5(28) with a fractional uncertainty of 9.1 * 10^-9 is free of systematic effects related to former high-pressure experiments. The reevaluated result for triton is mu_t/mu_p=1.066 639 908(10) with a fractional uncertainty of 9.3 * 10^-9.

physics.atom-ph↗
arXiv2003

The g factor of proton

We consider higher order corrections to the g factor of a bound proton in hydrogen atom and their consequences for a magnetic moment of free and bound proton and deuteron as well as some other objects.

hep-ph↗
arXiv2003

Simple Atoms, Quantum Electrodynamics and Fundamental Constants

This review is devoted to precision physics of simple atoms. The atoms can essentially be described in the framework of quantum electrodynamics (QED), however, the energy levels are also affected by the effects of the strong interaction due to the nuclear structure. We pay special attention to QED tests based on studies of simple atoms and consider the influence of nuclear structure on energy levels. Each calculation requires some values of relevant fundamental constants. We discuss the accurate determination of the constants such as the Rydberg constant, the fine structure constant and masses of electron, proton and muon etc.

hep-ph↗