294 research outputs found
Relativistic corrections of m\alpha^6 order to the ro-vibrational spectrum of H_2^+ and HD^+ molecular ions
The major goal of the high-precision studies of ro-vibrational states in the
hydrogen molecular ions is to provide an alternative way for improving the
electron-to-proton mass ratio, or the atomic mass of electron. By now the
complete set of relativistic and radiative corrections have been obtained for a
wide range of ro-vibrational states of H_2^+ and HD^+ up to order
R_\infty\alpha^4. In this work we complete calculations of various
contributions to the R_\infty\alpha^4 order by computing the relativistic
corrections to the binding energy of electron.Comment: 4 pages, 1 figur
Hyperfine structure of S states in Li and Be^+
A large-scale configuration-interaction (CI) calculation is reported for the
hyperfine splitting of the 2^2S and 3^2S states of ^7Li and ^9Be^+. The CI
calculation based on the Dirac-Coulomb-Breit Hamiltonian is supplemented with a
separate treatment of the QED, nuclear-size, nuclear-magnetization
distribution, and recoil corrections. The nonrelativistic limit of the CI
results is in excellent agreement with variational calculations. The
theoretical values obtained for the hyperfine splitting are complete to the
relative order of \alpha^2 and improve upon results of previous studies.Comment: 4 pages, 2 table
Vacuum polarization calculations for hydrogenlike and alkalilike ions
Complete vacuum polarization calculations incorporating finite nuclear size
are presented for hydrogenic ions with principal quantum numbers n=1-5.
Lithiumlike, sodiumlike, and copperlike ions are also treated starting with
Kohn-Sham potentials, and including first-order screening corrections. In both
cases dominant Uehling terms are calculated with high accuracy, and smaller
Wichmann- Kroll terms are obtained using numerical electron Green's functions.Comment: 23 pages, 1 figur
Hadronic Vacuum Polarization and the Lamb Shift
Recent improvements in the determination of the running of the fine-structure
constant also allow an update of the hadronic vacuum-polarization contribution
to the Lamb shift. We find a shift of -3.40(7) kHz to the 1S level of hydrogen.
We also comment on the contribution of this effect to the determination by
elastic electron scattering of the r.m.s. radii of nuclei.Comment: 7 pages, latex, 1 figure -- Submitted to Phys. Rev. A -- epsfig.sty
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Radiative Corrections to One-Photon Decays of Hydrogenic Ions
Radiative corrections to the decay rate of n=2 states of hydrogenic ions are
calculated. The transitions considered are the M1 decay of the 2s state to the
ground state and the E1(M2) decays of the and states to
the ground state. The radiative corrections start in order , but the method used sums all orders of . The leading
correction for the E1 decays is calculated and compared
with the exact result. The extension of the calculational method to parity
nonconserving transitions in neutral atoms is discussed.Comment: 22 pages, 2 figure
A New Tool for the Lamb Shift Calculation
We solve the Bethe-Salpeter equation for hydrogenic bound states by choosing
an appropriate interaction kernel . We want to use our solution to
calculate up to a higher order the hydrogen Lamb-shift, and as a first
application we present up to order \left(\aa / \pi\right)(\za)^7 the
contribution of the lowest order self-energy graph, calculated {\it exactly}.
The basic formalism is a natural extension to the hydrogenic bound states of
the one previously presented by R. Barbieri and E. Remiddi and used in the case
of positronium.Comment: 21 pages, Latex, Preprint DFUB-94-0
Lamb shift in muonic helium ion
The Lamb shift (2P_{1/2}-2S_{1/2}) in the muonic helium ion (mu ^4_2He)^+ is
calculated with the account of contributions of orders alpha^3, alpha^4,
alpha^5 and alpha^6. Special attention is given to corrections of the electron
vacuum polarization, the nuclear structure and recoil effects. The obtained
numerical value of the Lamb shift 1379.028 meV can be considered as a reliable
estimate for the comparison with experimental data.Comment: 18 pages, 11 figure
Lamb shift in muonic deuterium atom
We present new investigation of the Lamb shift (2P_{1/2}-2S_{1/2}) in muonic
deuterium (mu d) atom using the three-dimensional quasipotential method in
quantum electrodynamics. The vacuum polarization, nuclear structure and recoil
effects are calculated with the account of contributions of orders alpha^3,
alpha^4, alpha^5 and alpha^6. The results are compared with earlier performed
calculations. The obtained numerical value of the Lamb shift 202.4139 meV can
be considered as a reliable estimate for the comparison with forthcoming
experimental data.Comment: 24 pages, 11 figures. arXiv admin note: text overlap with
arXiv:hep-ph/061229
A cluster-separable Born approximation for the 3D reduction of the three-fermion Bethe-Salpeter equation
We perform a 3D reduction of the two-fermion Bethe-Salpeter equation based on
Sazdjian's explicitly covariant propagator, combined with a covariant
substitute of the projector on the positive-energy free states. We use this
combination in the two fermions in an external potential and in the
three-fermion problems. The covariance of the two-fermion propagators insures
the covariance of the two-body equations obtained by switching off the external
potential, or by switching off all interactions between any pair of two
fermions and the third one, even if the series giving the 3D potential is
limited to the Born term or more generally truncated. The covariant substitute
of the positive energy projector preserves the equations against continuum
dissolution without breaking the covariance.Comment: 21 pages, 1 figure This article has been deeply modified after
refereeing. The presentation has been improved and examples have been added.
Three subsections have been added (transition matrix elements, two-body
limits, covariant Salpeter's equation). submitted to Journal of Physics
Relativistic, QED, and nuclear mass effects in the magnetic shielding of He
The magnetic shielding of He is studied. The complete
relativistic corrections of order , leading QED corrections of
order , and finite nuclear mass effects of order
are calculated with high numerical precision. The resulting
theoretical predictions for are the most
accurate to date among all elements and support the use of He as a NMR
standard.Comment: 10 pages, corrected minor errors in Eqs.(6,7
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