共查询到20条相似文献,搜索用时 15 毫秒
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E. A. Kuraev L. N. Lipatov T. V. Shishkina 《Journal of Experimental and Theoretical Physics》2001,92(2):203-209
We consider radiative corrections to the electron and photon impact factors. The generalized eikonal representation for the e + e ? scattering amplitude at high energies and fixed momentum transfers is violated by nonplanar diagrams. An additional contribution to the two-loop approximation appears from the Bethe-Heitler mechanism of fermion pair production with the identity of the fermions in the final state taken into account. The violation of the generalized eikonal representation is also related to the charge parity conservation in QED. A one-loop correction to the photon impact factor for small virtualities of the exchanged photon is obtained using the known results for the cross section of the e + e ? production during photon-nuclei interactions. 相似文献
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The dependence of the exponential factor on the four-momentum carried by soft photons is studied. The dominant singularities with respect to q are taken into account to all orders in α and factored out. A method is proposed to evaluate the non-singular factor perturbatively. 相似文献
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A model of QED with conformally invariant gauge is considered. This gauge, being essentially nonlocal, is written in a local form by means of two nonphysical scalar fields. Using the BRST symmetry and the additional residual symmetry, a system of Ward identities is derived. These Ward identities are applied to prove the renormalizability of the model as well as to investigate the radiative corrections. A new class of conformal anomalies arises, connected with the absence of radiative corrections to the propagators including auxiliary fields. 相似文献
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H. Anlauf H. D. Dahmen P. Manakos T. Mannel T. Ohl 《Zeitschrift fur Physik C Particles and Fields》1991,52(4):655-658
We estimate the higher order QED corrections to the QED Compton events at HERA employing the leading logarithmic approximation to all orders in α. The Compton events are events of the typee+p→e′+γ+ Hadrons, wheree′ and γ have nearly balancedp T . 相似文献
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The contribution of exclusive radiative tail to the cross section of semi-inclusive hadron leptoproduction has been calculated exactly for the first time. Although the experience of inclusive data analyses suggests us that the contribution of radiative tail from the elastic peak is of particular importance, similar effects in the semi-inclusive process were only recently estimated in the peaking approximation. The explicit expressions for the lepton part of the lowest order QED contribution of exclusive radiative tail to the five-fold differential cross section are obtained and discussed. Numerical estimates, provided within Jefferson Lab kinematic conditions, demonstrate rather large effects of the exclusive radiative tail in the region at semi-inclusive threshold and for high energy of detected hadron. 相似文献
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We discuss the τ polarization measurement at SLC/LEP energies as a data point in the precision tests of the Glashow-Salam-Weinberg model. Theoretical and experimental uncertainties of this measurement are examined and it is concluded that apart from left-right asymmetry measurement, and for typical values of the parameters of the Standard Model, the τ polarization offers the best probe of the couplings of leptons to the Z0. In particular, the dependence of the τ polarization on the top and Higgs masses is discussed. The interplay of QED initial state bremsstrahlung and other classes of radiative corrections is also discussed. 相似文献
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B. A. van Tiggelen S. Kawka G. L. J. A. Rikken 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2012,66(10):1-10
We develop a QED approach to find the contribution of the quantum vacuum to the electromagnetic Abraham force. Semi-classical theories predict diverging contributions from the quantum vacuum. We show that the divergencies disappear by Kramers-Bethe mass-renormalization. The finite remainder is compared to the relativistic corrections to the Abraham force. This work applies an earlier approach [S.?Kawka, B.A. van Tiggelen, Europhys Lett. 89, 11002 (2010)]1, dedicated to the simpler case of a harmonic oscillator, to the Coulomb interaction, which is more realistic in a QED context. 相似文献
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M. Znojil 《Czechoslovak Journal of Physics》1991,41(3):201-208
In the quantum-mechanical context, we advocate the use of (integral) Heisenberg equations, the non-numerical solutions of which may be generated by iterations. In an illustrative application to the general (polynomial) oscillators, elementary coefficients result as an additional and unexpected merit of our generalized Peano-Baker solutions. 相似文献
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P. Indelicato J. P. Santos S. Boucard J.-P. Desclaux 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,45(1):155-170
In this paper we review the different relativistic and QED contributions to energies, ionic radii, transition probabilities
and Landé g-factors in super-heavy elements, with the help of the MultiConfiguration Dirac-Fock method (MCDF). The effects
of taking into account the Breit interaction to all orders by including it
in the self-consistent field process are demonstrated. State of the art radiative corrections are included in the calculation
and discussed. We also study the non-relativistic limit of MCDF calculation and
find that the non-relativistic offset can be unexpectedly large. 相似文献
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B. d'Espagnat 《Foundations of Physics》1992,22(12):1495-1504
The idea is discussed according to which, in the Heisenberg picture, the operators correspond to the dynamic properties while the density matrix corresponds to our knowledge. A simple, soluble model is made use of in order to determine in what way this idea needs to be refined and what it then tells us about the relationship of reality and physics. 相似文献
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P. Castelo Ferreira J. Dias de Deus 《The European Physical Journal C - Particles and Fields》2008,54(4):539-545
We compute QCD corrections to QED calculations for vacuum polarization in background magnetic fields. Formally, the diagram
for virtual eē loops is identical to the one for virtual qq̄ loops. However, due to confinement, or to the growth of αs as p2 decreases, a direct calculation of the diagram is not allowed. At large p2 we consider the virtual qq̄ diagram, in the intermediate region we discuss the role of the contribution of quark condensates
〈qq̄〉 and at the low-energy limit we consider the π0, as well as charged pion π+π- loops. Although these effects seem to be out of the measurement accuracy of photon–photon laboratory experiments, they may
be relevant for γ-ray burst propagation. In particular, for emissions from the center of the galaxy (8.5 kpc), we show that
mixing between the neutral pseudo-scalar pion π0 and photons renders a deviation from the power-law spectrum in the TeV range. For scalar quark condensates 〈qq̄〉 and virtual
qq̄ loops are relevant only for very high radiation density ∼300 MeV/fm3 and very strong magnetic fields of order ∼1014 T.
PACS 12.20.Ds; 14.40.-n; 12.38.Aw; 14.65.Bt 相似文献
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Peter J Mohr 《Annals of Physics》1974,88(1):26-51
The one-photon self-energy radiative level shift of an electron in a Coulomb field is examined. An expression for the level shift which is suitable for direct numerical evaluation, for Z in the range 10–110, is obtained. It is based on the known Coulomb radial Green's functions and not on a power series expansion in Zα. In the following paper, the numerical evaluation of the level shift for the state is described. 相似文献
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Complete relativistic and quantum electrodynamics corrections of order alpha(2) Ry and alpha(3) Ry are calculated for the ground state of the beryllium atom and its positive ion. A basis set of correlated Gaussian functions is used, with exponents optimized against nonrelativistic binding energies. The results for Bethe logarithms ln(k(0)(Be)=5.750 34(3) and ln(k(0)(Be+)=5.751 67(3) demonstrate the availability of high precision theoretical predictions for energy levels of the beryllium atom and light ions. Our recommended value of the ionization potential 75 192.514(80) cm(-1) agrees with equally accurate available experimental values. 相似文献