1,083 research outputs found
Bogoliubov compensation approach in QCD and in the electroweak theory
We describe application of Bogoliubov compensation principle to calculation
of non-perturbative contribution in the electroweak theory and QCD. We obtain
unique solutions of compensation equations, which impose strong restrictions on
parameters of theories and on functional dependence of corresponding
form-factors. We calculate value of running gauge electroweak coupling
, that differs from the experimental value less than by
10%. We derive effective Nambu-Jona-Lasinio interaction from fundamental QCD
and express its parameters in terms of initial QCD parameters: at
low-momenta and current mass of light quarks. This leads to satisfactory
description of low-mass hadron physics.Comment: 6 pages, no figures, talk presented at the International Bogolyubov
Conference, August 21-27, 2009, Moscow-Dubna, Russi
Spontaneous generation of the Nambu --Jona-Lazinio interaction in quantum chromodynamics with two light quarks
In QCD with two light quarks with application of Bogolubov quasi-averages
approach a possibility of spontaneous generation of an effective interaction,
leading to the Nambu -- Jona-Lazinio model, is studied. Compensation equations
for form-factor of the interaction is shown to have the non-trivial solution
leading to theory with two parameters: average low-energy value of
and dimensional parameter . All other parameters: the current and the
constituent quark masses, the quark condensate, mass of meson, mass of
meson and its width are expressed in terms of the two initial
parameters in satisfactory correspondence to experimental phenomenology. The
results being obtained allow to state an applicability of the approach in the
low-energy hadron physics and promising possibilities of its applications to
other problems.Comment: 16 pages, 1 table, 3 figure
Observations on the radiative corrections to pion beta-decay
We find that, in the local V-A theory, the radiative corrections to pion
beta-decay involving the weak vector current, when evaluated in the current
algebra (CA) formulation in which quarks are the fundamental underlying fields,
show a small difference with the more elementary calculations based directly on
the pion fields. We show that this difference arises from a specific
short-distance effect that depends on the algebra satisfied by the weak and
electromagnetic currents. On the other hand, we present a simple theoretical
argument that concludes that this difference does not occur when the CA
formulation is compared with the chiral perturbation theory (chiPT) approach.
Comparisons with previous studies, and with a more recent calculation based on
chiPT, are included. We also briefly review the important differences between
the results in the local V-A theory and the Standard Model.Comment: 5 pages, 1 figure. V2: two paragraphs have been added in Section III.
Final version on PR
The running of the electromagnetic coupling alpha in small-angle Bhabha scattering
A method to determine the running of alpha from a measurement of small-angle
Bhabha scattering is proposed and worked out. The method is suited to high
statistics experiments at e+e- colliders, which are equipped with luminometers
in the appropriate angular region. A new simulation code predicting small-angle
Bhabha scattering is also presentedComment: 15 pages, 3 Postscript figure
O(\alpha^2 \ln(m_\mu/m_e)) Corrections to Electron Energy Spectrum in Muon Decay
O(\alpha^2 \ln(m_\mu/m_e)) corrections to electron energy spectrum in muon
decay are computed using perturbative fragmentation function approach. The
magnitude of these corrections is comparable to anticipated precision of the
TWIST experiment at TRIUMF where Michel parameters will be extracted from the
measurement of the electron energy spectrum in muon decay.Comment: 8 pages, LaTeX, revtex4.cls, 1 PostScript figur
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