QED radiative corrections to elastic electron–proton scattering at low energies are discussed. Corrections to the electron line and effects due to vacuum polarization are computed. Higher order ...effects are estimated for the conditions of the experiment on the electric and magnetic proton form factors by the A1 Collaboration. Calculations are performed within the next-to-leading approximation. The inclusion of the higher order effects can affect the value of the proton charge radius extracted from the experimental data.
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Fab Four self-interaction in quantum regime Arbuzov, A. B.; Latosh, B. N.
The European physical journal. C, Particles and fields,
10/2017, Volume:
77, Issue:
10
Journal Article
Peer reviewed
Open access
Quantum behavior of the John Lagrangian from the Fab Four class of covariant Galileons is studied. We consider one-loop corrections to the John interaction due to cubic scalar field interaction. ...Counter terms are calculated, one appears because of massless scalar field theory infrared issues, another one lies in the George class, and the rest of them can be reduced to the initial Lagrangian up to surface terms. The role of quantum corrections in the context of cosmological applications is discussed.
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A
bstract
Radiative muon and tau lepton decays are described within the model-independent approach with the help of generalized Michel parameters. The exact dependence on charged lepton masses is ...taken into account. The results are relevant for modern and future experiments on muon and tau lepton decays.
Abstract
Perturbative solutions for unpolarized QED parton distribution and fragmentation functions are presented explicitly in the next-to-leading logarithmic approximation. The scheme of iterative ...solution of QED evolution equations is described in detail. Terms up to
(
α
3
L
2
)
are calculated analytically, where
L
=
ln
(
μ
F
2
/
m
e
2
)
is the large logarithm which depends on the factorization energy scale
μ
F
≫
m
e
. The results are process independent and relevant for future high-precision experiments.
ZFITTER is a Fortran program for the calculation of fermion pair production and radiative corrections at high energy
e
+
e
−
colliders; it is also suitable for other applications where electroweak ...radiative corrections appear.
ZFITTER is based on a semi-analytical approach to the calculation of radiative corrections in the Standard Model. We present a summary of new features of the
ZFITTER program version 6.42 compared to version 6.21. The most important additions are: (i) some higher-order QED corrections to fermion pair production, (ii) electroweak one-loop corrections to atomic parity violation, (iii) electroweak one-loop corrections to
ν
¯
e
ν
e
production, (iv) electroweak two-loop corrections to the
W boson mass and the effective weak mixing angle.
Title of program:
ZFITTER version 6.42 (18 May 2005)
Catalogue identifier:ADMJ_v2_0
Program summary URL:
http://cpc.cs.qub.ac.uk/summaries/ADMJ_v2_0
Authors of original program: D. Bardin, P. Christova, M. Jack, L. Kalinovskaya, A. Olshevski, S. Riemann, T. Riemann
Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland
Reference for
ZFITTER version 6.21:
D. Bardin et al., Comput. Phys. Comm. 133 (2001) 229–395
Operating system:
UNIX/LINUX, program tested under, e.g.,
HP-UX and
PC/Linux
Programming language used:
FORTRAN 77
High speed storage required: <2 MB
No. of lines in distributed program, including test data, etc.:29 164
No. of bytes in distributed program, including test data, etc.:185 824
Distribution format:tar.gz
Does the new version supersede the previous version:Yes
Nature of the physical problem: Fermion pair production is an important reaction for precision tests of the Standard Model, at LEP/SLC and future linear colliders at higher energies. For this purpose, QED, electroweak and QCD radiative corrections have to be calculated with high precision, including higher order effects. Multi parameter fits used to extract model parameters from experimental measurements require a program of sufficient flexibility and high calculational speed.
ZFITTER combines these two aspects by employing analytical integrations of matrix elements and at most one-dimensional numerical integration, as well as a variety of flags defining the physics content used. The calculated predictions are typically at the per mille precision level, sometimes better.
Method of solution: Numerical integration of analytical formulae.
Reasons for new version:Addition of substantial material into the code: covering of more reactions; more accurate description of existing reactions.
Summary of revisions:New parts for predicting atomic parity violation and for neutrino pair production; more accurate higher order QED corrections for fermion pair production; two-loop corrections to the predictions of
W mass and of the weak mixing angle.
Restrictions on the complexity of the problem: Fermion pair production is described below the top quark pair production threshold. Photonic corrections are taken into account with simple cuts on photon energy, or the energies and acollinearity of the two fermions, and
one fermion production angle. The treatment of Bhabha scattering is less advanced.
Typical running time: On a Pentium IV PC installation (2.8 GHz) using g77 under Linux 2.4.21, approximately 23 s are needed to run the standard test of subroutine
ZFTEST. This result is for a
default/recommended setting of the input parameters, with
all corrections in the Standard Model switched
on.
ZFTEST computes 12 cross-sections and cross-section asymmetries for 8 energies with 5 interfaces, i.e. about 360 cross-sections in 23 s.
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The extended Nambu-Jona-Lasinio model is briefly described and various ways to apply it are demonstrated. Theoretical approaches to the low-energy meson production processes in colliding ...electron-positron beams and tau-lepton decays are reviewed. The processes considered occur via intermediate scalar, vector, and axial-vector mesons in the ground state and in the first radially excited state. The model uses the concept of spontaneous chiral symmetry breaking to describe such states. Experimental and theoretical comparisons with other phenomenological strong interaction models are presented.
Radiative corrections due to initial state radiation in electron-positron annihilation are calculated within the QED structure function approach. Results are shown in the next-to-leading logarithmic ...approximation up to O ( α 4 L 3 ) order, where L = ln ( s / m e 2 ) is the large logarithm. Several mistakes in previous calculations are corrected. The results are relevant for future high-precision experiments at e + e − colliders. Published by the American Physical Society 2024
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