47 research outputs found
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.Comment: presented at The International Workshop "e+e- collisions from phi to
psi
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
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.Comment: An invited talk at HYPER symposium (Paris, 2002
Logarithmic two-loop corrections to the Lamb shift in hydrogen
Higher order logarithmic corrections to the
hydrogen Lamb shift are calculated. The results obtained show the two-loop
contribution has a very peculiar behavior, and significantly alter the
theoretical predictions for low lying S-states.Comment: 14 pages, including 2 figures, submitted to Phys. Rev. A, updated
with minor change
Hadronic effects in leptonic systems: muonium hyperfine structure and anomalous magnetic moment of muon
Contributions of hadronic effects to the muonium physics and 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.Comment: Presented at PSAS 2002 (St. Petersburg
Three-Loop Radiative-Recoil Corrections to Hyperfine Splitting in Muonium
We calculate three-loop radiative-recoil corrections to hyperfine splitting
in muonium generated by the diagrams with the first order electron and muon
polarization loop insertions in graphs with two exchanged photons. These
corrections are enhanced by the large logarithm of the electron-muon mass
ratio. The leading logarithm squared contribution was obtained a long time ago.
Here we calculate the single-logarithmic and nonlogarithmic contributions. We
previously calculated the three-loop radiative-recoil corrections generated by
two-loop polarization insertions in the exchanged photons. The current paper
therefore concludes calculation of all three-loop radiative-recoil corrections
to hyperfine splitting in muonium generated by diagrams with closed fermion
loop insertions in the exchanged photons. The new results obtained here improve
the theory of hyperfine splitting, and affect the value of the electron-muon
mass ratio extracted from experimental data on the muonium hyperfine splitting.Comment: 27 pages, 6 figures, 7 table
Virtual annihilation contribution to orthopositronium decay rate
Order alpha^2 contribution to the orthopositronium decay rate due to
one-photon virtual annihilation is found to be
delta Gamma = (alpha/pi)^2 (pi^2 ln(alpha) - 0.8622(9))Gamma_LO.Comment: 2 pages, no figure
Semi-Analytic Approach to Higher-Order Corrections in Simple Muonic Bound Systems: Vacuum Polarization, Self-Energy and Radiative-Recoil
The current discrepancy of theory and experiment observed recently in muonic
hydrogen necessitates a reinvestigation of all corrections to contribute to the
Lamb shift in muonic hydrogen muH, muonic deuterium muD, the muonic 3He ion, as
well as in the muonic 4He ion. Here, we choose a semi-analytic approach and
evaluate a number of higher-order corrections to vacuum polarization (VP)
semi-analytically, while remaining integrals over the spectral density of VP
are performed numerically. We obtain semi-analytic results for the second-order
correction, and for the relativistic correction to VP. The self-energy
correction to VP is calculated, including the perturbations of the Bethe
logarithms by vacuum polarization. Subleading logarithmic terms in the
radiative-recoil correction to the 2S-2P Lamb shift of order alpha (Zalpha)^5
mu^3 ln(Zalpha)/(m_mu m_N) are also obtained. All calculations are
nonperturbative in the mass ratio of orbiting particle and nucleus.Comment: 10 pages; svjour style; to appear in the European Physical Journal
QED theory of the nuclear recoil effect on the atomic g factor
The quantum electrodynamic theory of the nuclear recoil effect on the atomic
g factor to all orders in \alpha Z and to first order in m/M is formulated. The
complete \alpha Z-dependence formula for the recoil correction to the
bound-electron g factor in a hydrogenlike atom is derived. This formula is used
to calculate the recoil correction to the bound-electron g factor in the order
(\alpha Z)^2 m/M for an arbitrary state of a hydrogenlike atom.Comment: 17 page