98 research outputs found
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
NEW CORRECTIONS OF ORDER AND TO THE LAMB SHIFT
Two corrections to the Lamb shift, induced by the polarization operator
insertions in the external photon lines are calculated.Comment: 4 pages, revtex, no figure
Radiative-nonrecoil corrections of order alpha^2 (Z alpha) E_F to the hyperfine splitting of muonium
We present results for the corrections of order alpha^2 (Z alpha) E_F to the
hyperfine splitting of muonium. We compute all the contributing Feynman
diagrams in dimensional regularization and a general covariant gauge using a
mixture of analytical and numerical methods. We improve the precision of
previous results.Comment: 5 pages, 3 figures; v2: corrected several typos and replaced figure
3, final results and conclusions unchange
Radiative Corrections to the Muonium Hyperfine Structure. I. The Correction
This is the first of a series of papers on a systematic application of the
NRQED bound state theory of Caswell and Lepage to higher-order radiative
corrections to the hyperfine structure of the muonium ground state. This paper
describes the calculation of the radiative correction. Our
result for the complete correction is 0.424(4) kHz, which
reduces the theoretical uncertainty significantly. The remaining uncertainty is
dominated by that of the numerical evaluation of the nonlogarithmic part of the
term and logarithmic terms of order .Comment: 56 pages, Rev.tex V3.0 and epsf.tex. 12 postscript files are called
in the text. Version accepted by Phys. Rev. D. A new table is adde
Radiative-nonrecoil corrections of order alpha^2 (Z alpha)^5 to the Lamb shift
We present results for the corrections of order alpha^2 (Z alpha)^5 to the
Lamb shift. We compute all the contributing Feynman diagrams in dimensional
regularization and a general covariant gauge using a mixture of analytical and
numerical methods. We confirm results obtained by other groups and improve
their precision. Values of the 32 master integrals for this and similar
problems are provided.Comment: 8 pages, 4 figures; v2: added two references, changed comparison with
previous result, conclusions unchanged, matches published version; v3:
corrected typo in Table I, final results and conclusions unchange
Two-Loop Effects and Current Status of the 4He+ Lamb Shift
We report on recent progress in the treatment of two-loop binding corrections
to the Lamb shift, with a special emphasis on S and P states. We use these and
other results in order to infer an updated theoretical value of the Lamb shift
in 4He+.Comment: 11 pages, nrc1 style; paper presented at PSAS (2006), Venic
Universality of Leading Relativistic Corrections to Bound State Gyromagnetic Ratios
We discuss the leading relativistic (nonrecoil and recoil) corrections to
bound state -factors of particles with arbitrary spin. These corrections are
universal for any spin and depend only on the free particle gyromagnetic
ratios. We explain the physical reasons behind this universality.Comment: 10 pp., based on talks given at the Gribov-80 Memorial Workshop,
ICTP, Trieste, Italy, May 2010 and at PSAS 2010 workshop, Les Houches, June
2010. To be published in the Gribov-80 Proceedings and in Can. J. Phy
The second-order electron self-energy in hydrogen-like ions
A calculation of the simplest part of the second-order electron self-energy
(loop after loop irreducible contribution) for hydrogen-like ions with nuclear
charge numbers is presented. This serves as a test for the
more complicated second-order self-energy parts (loop inside loop and crossed
loop contributions) for heavy one-electron ions. Our results are in strong
disagreement with recent calculations of Mallampalli and Sapirstein for low
values but are compatible with the two known terms of the analytical
-expansion.Comment: 13 LaTex pages, 2 figure
Loop-after-loop contribution to the second-order Lamb shift in hydrogenlike low-Z atoms
We present a numerical evaluation of the loop-after-loop contribution to the
second-order self-energy for the ground state of hydrogenlike atoms with low
nuclear charge numbers Z. The calculation is carried out in the Fried-Yennie
gauge and without an expansion in Z \alpha. Our calculation confirms the
results of Mallampalli and Sapirstein and disagrees with the calculation by
Goidenko and coworkers. A discrepancy between different calculations is
investigated. An accurate fitting of the numerical results provides a detailed
comparison with analytic calculations based on an expansion in the parameter Z
\alpha. We confirm the analytic results of order \alpha^2 (Z\alpha)^5 but
disagree with Karshenboim's calculation of the \alpha^2 (Z \alpha)^6 \ln^3(Z
\alpha)^{-2} contribution.Comment: RevTex, 19 pages, 4 figure
Bosonization and generalized Mandelstam soliton operators
The generalized massive Thirring model (GMT) with three fermion species is
bosonized in the context of the functional integral and operator formulations
and shown to be equivalent to a generalized sine-Gordon model (GSG) with three
interacting soliton species. The generalized Mandelstam soliton operators are
constructed and the fermion-boson mapping is established through a set of
generalized bosonization rules in a quotient positive definite Hilbert space of
states. Each fermion species is mapped to its corresponding soliton in the
spirit of particle/soliton duality of Abelian bosonization. In the
semi-classical limit one recovers the so-called SU(3) affine Toda model coupled
to matter fields (ATM) from which the classical GSG and GMT models were
recently derived in the literature. The intermediate ATM like effective action
possesses some spinors resembling the higher grading fields of the ATM theory
which have non-zero chirality. These fields are shown to disappear from the
physical spectrum, thus providing a bag model like confinement mechanism and
leading to the appearance of the massive fermions (solitons). The ordinary
MT/SG duality turns out to be related to each SU(2) sub-group. The higher rank
Lie algebra extension is also discussed.Comment: 22 pages, LaTex. Some misprints were corrected. Published in Eur.Phys
J.
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