64 research outputs found
Symmetries of higher-spin fields and the electromagnetic N-N(1680) form factors
We study the Q^2-evolution of the form factors (FFs) for the
nucleon-to-N(1680) transition in the framework of an effective field theory. To
this end, the intrinsic symmetries of the spin-5/2 Rarita-Schwinger (RS) fields
are analyzed, and a Lagrangian of the electromagnetic N-N(1680) interactions is
constructed. The Lagrangian preserves all the intrinsic symmetries of the
spin-5/2 field--point and gauge invariance--and does not involve lower-spin
components of the reducible RS field. Besides, the symmetries postulate the
definitions of the Lagrangian FFs. These FFs are modeled as dispersionlike
expansions in a vector-meson--dominance model. A good agreement with the
experimental data is achieved.Comment: 11 pp., 2 fig
The gauge model of quark-meson interactions and its application to the meson radiative decays
To analyze an electromagnetic and strong hadron processes at low energies, we
consider the renormalizable model with the U0(1) x U(1) x SU(2) gauge symmetry.
This approach is based on the linear sigma-model extended by the gauge and
quark-meson interactions. Physical content and parameters of the model are
discussed. Theoretical predictions for some radiative decays of vector mesons
are in a good agreement with the experimental data.Comment: 19 pages, 4 figure
Invariant dynamics of scalar perturbations of inflanton and gravitational fields
A gauge-independent, invariant theory of linear scalar perturbations of
inflation and gravitational fields has been created. This invariant theory
allows one to compare gauges used in the work of other researchers and to find
the unambiguous criteria to separate the physical and coordinate effects. It is
shown, in particular, that the so-called longitudial gauge, commonly used when
considering inflation instability, leads to a fundamental overestimation of the
effect because of non-physical perturbations of the proper time in the frame of
reference specified by this gauge. Back reaction theories employing this sort
of gauge [1] also involve coordinate effects. The invariant theory created here
shows that the classical Lifshitz (1946) [2] gauge does not lead to
non-physical perturbations of the proper time and can be used to analyze the
inflation regime and the back reaction of perturbations on this regime
properly. The first theory of back reaction on background of all types of
perturbations (scalar, vector and tensor) based on this gauge was published in
1975 [3] and has been applied recently to the inflation [4]. The investigation
of long-length perturbations, which characterize the stability of the
inflationary process, and quantum fluctuations, which form the
Harrison-Zel'dovich spectrum at the end of inflation, is performed in the
invariant form. The invariant theory proposed allows one to examine the effect
of quantum fluctuations on the inflationary stage when the periodic regime
changes to an aperiodic one. That only the invariant theory must be used to
analyze space experiments is one of the conclusions of the present work.Comment: poster at Symposium "The Dark Universe: Matter, Energy, and Gravity"
2 - 5 April 2001, Space Telescope Science Institute, Baltimore, Maryland
2121
The gauge model of quark--meson interactions and the Higgs status of scalar mesons
Electromagnetic and strong hadron processes at low energies are considered in
the renormalizable model with the spontaneously broken gauge symmetry. Calculated radiative widths of vector mesons and
effective couplings agree with the experimental data. Residual Higgs
degrees of freedom are associated with scalar states and
with the degeneration in masses. Two-gamma decays of and
mesons are analyzed in detail. To provide an "infrared confinement" a cutoff
procedure has been also used in calculations.Comment: 8 pages, 1 figur
Cosmology of gravitational vacuum
Production of gravitational vacuum defects and their contribution to the
energy density of our Universe are discussed. These topological microstructures
(defects) could be produced in the result of creation of the Universe from
"nothing" when a gravitational vacuum condensate has appeared. They must be
isotropically distributed over the isotropic expanding Universe. After Universe
inflation these microdefects are smoothed, stretched and broken up. A part of
them could survive and now they are perceived as the structures of Lambda-term
and an unclustered dark matter. It is shown that the parametrization
noninvariance of the Wheeler-De Witt equation can be used to describe
phenomenologically vacuum topological defects of different dimensions
(worm-holes, micromembranes, microstrings and monopoles). The mathematical
illustration of these processes may be the spontaneous breaking of the local
Lorentz-invariance of the quasi-classical equations of gravity. Probably the
gravitational vacuum condensate has fixed time in our Universe. Besides,
3-dimensional topological defects renormalize Lambda-term.Comment: 8 pages, Preprint of Lebedev Physical Institute No 9, 200
Estimation of charm production cross section in hadronic interactions at high energies
Results of processing experimental data on charm production in hadron-hadron
interactions are presented. The analysis is carried out within the frame of
phenomenological model of diffraction production and quark statistics based on
additive quark model (AQM). In low energy region sqrt s = 20 - 40GeV, the cross
sections si_ {pN to c bar cX} (s), si_ {pi N to c bar cX} (s) are fitted by
logarithmic function with the parameters connected by relationship of AQM.
At collider energies 200, 540, 900, 1800 GeV, the values of si_{bar pp to c
bar cX} (s) were obtained by a quark statistics method from the data on
diffraction dissociation. It is established, that logarithmic function with
universal numerical parameters describes the whole set of low-energy and
high-energy data with high accuracy. The expected values of cross sections are
si_{pp to c bar cX} = 250 pm 40 mu b and 355 pm 57 mu b at TEVATRON energy sqrt
{s} = 1.96 TeV and LHC energy sqrt {s} = 14 TeV accordingly. Opportunities of
use of the obtained results for calibration of a flux of "prompt" muons in
high-energy component of cosmic rays are discussed.Comment: 7 pages, 3 figure
The New Scenario of the Initial Evolution of the Universe
We propose that the Universe created from "nothing" with relatively small
particles number and quickly relaxed to quasiequilibrium state at the Planck
parameters. The classic cosmological solution for this Universe with
Lambda-term has two branches divided by the gap. The quantum process of
tunneling between the cosmological solution branches and kinetic of the second
order relativistic phase transition in supersymmetric SU(5) model on the GUT
scale are investigated by numerical methods. Einstein equations was solved
together with the equations of relaxation kinetics. Other quantum
geometrodynamics process (the bounce from singularity) and the Wheeler- De Witt
equation are investigated also. For the formation of observable particles
number the model of the slowly swelling Universe in the result of the multiple
reproduction of cosmological cycles is arised naturally.Comment: 11 pages (RevTex), 5 PostScript figures. Submitted to Physical Review
Letter
Preons, Dark Matter and the Production of Early Cosmological Structures
If the preon structure of quarks, leptons and gauge bosons will be proved
then in the Universe during relativistic phase transition the production of
nonperturbative preon condensates has been occured collective excitations of
which are perceived as pseudogoldstone bosons. Dark matter consisting of
pseudogoldstone bosons of familon type contains a "hot" component from massless
particles and a "cold" (nonrelativistic) component from massive particles. It
is shown that such dark matter was undergone to two relativistic phase
transitions temperatures of which were different. In the result of these phase
transitions the structurization of dark matter and therefore the baryon
subsystem has taken place. Besides, the role of particle generations in the
Universe become more evident. For the possibility of structurization of matter
as minimum three generations of particles are necessary.Comment: LaTeX 2.09, 13 pages, 1 Postscript figur
The Selforganization of Vacuum, Phase Transitions and the Cosmological Constant
The problem of the physical nature and the cosmological genesis of
Lambda-term is discussed. This problem can't be solved in terms of the current
quantum field theory which operates with Higgs and non-perturbative vacuum
condensates and takes into account the changes of these condensates during
relativistic phase transitions. The problem can't be completely solved also in
terms of the conventional global quantum theory: Wheeler-DeWitt quantum
geometrodynamics does not describe the evolution of the Universe in time (RPT
in particular). We have investigated this problem in the context of energies
density of different vacuum subsystems characteristic scales of which pervaid
all energetic scale of the Universe. At first the phemenological solution of
Lambda-term problem and then the hypothesis about the possible structure of a
new global quantum theory are proposed. The main feature of this theory is the
inreversible evolution of geometry and vacuum condensates in time in the regime
of their selforganization. The transformation of the cosmological constant in
dynamical variable is inevitably.Comment: LaTex 2.09, 10 page
Total gamma-N cross section in the energy range sqrt(s)=40-250 GeV
The results of measurements of gamma-N total cross section, obtained by the
method of photoproduction processes registration at the Baksan Underground
Scintillation Telescope, are presented. These data at energies sqrt(s)=40-130
GeV confirm the effect of more rapid photon-hadron cross-section rise as
compared to the hadron-hadron ones. It is shown, the increasing of the additive
quark number in the products of photon hadronization can be one of the causes
responsible for this effect. On the basis of the analysis of experimental data
on both gamma-N and gamma-gamma total cross sections, the status of direct and
indirect cross-section measurements is discussed
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