64 research outputs found

    Symmetries of higher-spin fields and the electromagnetic N-N(1680) form factors

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    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

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    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

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    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

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    Electromagnetic and strong hadron processes at low energies are considered in the renormalizable model with the spontaneously broken U0(1)×U(1)×SU(2)U_0(1)\times U(1)\times SU(2) gauge symmetry. Calculated radiative widths of vector mesons and effective couplings gVVSg_{VVS} agree with the experimental data. Residual Higgs degrees of freedom are associated with scalar states a0(980)a_0(980) and f0(980)f_0(980) with the degeneration in masses. Two-gamma decays of π0−\pi^0- and σ−\sigma- 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

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    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

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    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

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    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

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    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

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    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

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    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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