96 research outputs found
Upper bound on the cutoff in lattice Electroweak theory
We investigate numerically lattice Weinberg - Salam model without fermions
for realistic values of the fine structure constant and the Weinberg angle. We
also analyze the data of the previous numerical investigations of lattice
Electroweak theory. We have found that moving along the line of constant
physics when the lattice spacing is decreased, one should leave the
physical Higgs phase of the theory at a certain value of . Our estimate of
the minimal value of the lattice spacing is .Comment: Latex, 21 pages, 3 figures, to appear in JHE
Central Dominance and the Confinement Mechanism in Gluodynamics
New topological objects, which we call center monopoles, naturally arise in
the Maximal Center Projection of SU(3) gluodynamics. The condensate of the
center monopoles is the order parameter of the theory.Comment: 4 pages revtex, 3 figure
A hidden symmetry in the Standard Model
We found an additional symmetry hidden in the fermion and Higgs sectors of
the Standard Model. It is connected to the centers of the SU(3) and SU(2)
subgroups of the gauge group. A lattice regularization of the whole Standard
Model is constructed that possesses this symmetry.Comment: 6 pages, no figures. Shortened versio
Light-Front Singularities
Calculations in light-front quantization are sometimes found to lead to singularities that are not present in the corresponding manifestly covariant treatment. We give some examples that were found in the framework of perturbation theory, but must also occur in nonperturbative calculations. In the case of anomalies, regularization-scheme dependences were found that not only occur between the light-front approach and manifestly covariant calculations, but also among the latter ones. © 2010 The Author(s)
Relativistic bound-state calculations in Light Front Dynamics
We calculated bound states in the quantum field theoretical approach. Using
the Wick-Cutkosky model and an extended version of this model (in which a
particle with finite mass is exchanged) we have calculated the bound states in
the scalar case.Comment: 3 pages, proceedings of the Light Cone Meeting Trento 2001, to be
published in Nucl. Phys. B - Proceedings Supplement
Abelian Monopoles and Action Density in SU(2) Gluodynamics on the Lattice
We show that the extended Abelian magnetic monopoles in the Maximal Abelian
projection of lattice SU(2) gluodynamics are locally correlated with the
magnetic and the electric parts of the SU(2) action density. These correlations
are observed in the confined and in the deconfined phases.Comment: 11 pages, LaTeX2e, 5 figures, uses epsf.sty; revision: Introduction
is extended and a few references are adde
The Vector Meson Form Factor Analysis in Light-Front Dynamics
We study the form factors of vector mesons using a covariant fermion field
theory model in dimensions. Performing a light-front calculation in the
frame in parallel with a manifestly covariant calculation, we note the
existence of a nonvanishing zero-mode contribution to the light-front current
and find a way of avoiding the zero-mode in the form factor calculations.
Upon choosing the light-front gauge (\ep^+_{h=\pm}=0) with circular
polarization and with spin projection , only the
helicity zero to zero matrix element of the plus current receives zero-mode
contributions. Therefore, one can obtain the exact light-front solution of the
form factors using only the valence contribution if only the helicity
components, , and , are used. We also compare our
results obtained from the light-front gauge in the light-front helicity basis
(i.e. ) with those obtained from the non-LF gauge in the instant form
linear polarization basis (i.e. ) where the zero-mode contributions to
the form factors are unavoidable.Comment: 33 pages; typo in Eq.(15) is corrected; comment on Ref.[9] is
corrected; version to appear in Phys. Rev.
Standard Model with the additional symmetry on the lattice
An additional symmetry hidden in the fermion and Higgs sectors of the
Standard Model has been found recently\cite{BVZ2003}. A lattice regularization
of the Standard Model was constructed that possesses this symmetry. In
\cite{BVZ2004} we have reported our results on the numerical simulation of the
Electroweak sector of the model. In this paper we report our results on the
numerical simulation of the full () model. The
phase diagram of the model has been investigated using static quark and lepton
potentials. Various types of monopoles have been constructed. Their densities
appear to be sensitive to the phase transition lines. Differences between the
realizations of the Standard Model which do or do not possess the mentioned
symmetry, are discussed.Comment: Latex, 14 page
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