66 research outputs found
Ferromagnetic properties of charged vector boson condensate
Bose-Einstein condensation of W bosons in the early universe is studied. It
is shown that, in the broken phase of the standard electroweak theory,
condensed W bosons form a ferromagnetic state with aligned spins. In this case
the primeval plasma may be spontaneously magnetized inside macroscopically
large domains and form magnetic fields which may be seeds for the observed
today galactic and intergalactic fields. However, in a modified theory, e.g. in
a theory without quartic self interactions of gauge bosons or for a smaller
value of the weak mixing angle, antiferromagnetic condensation is possible. In
the latter case W bosons form scalar condensate with macroscopically large
electric charge density i.e. with a large average value of the bilinear product
of W-vector fields but with microscopically small average value of the field
itself.Comment: Some numerical estimates and discussions are added according to the
referee's suggestions. This version is accepted for publication in JCA
Extra quark-lepton generations and precision measurements
The existence of extra chiral generations with all fermions heavier than M_Z
is strongly disfavoured by the precision electroweak data. However the data are
fitted nicely even by a few extra generations, if one allows neutral leptons to
have masses close to 50 GeV. The data allow inclusion of one additional
generation of heavy fermions in SUSY extension of Standard Model if chargino
and neutralino have masses close to 60 GeV with \Delta m =~ 1 GeV.Comment: 14 pages, 5 figure
Cosmological Implications of Neutrinos
The lectures describe several cosmological effects produced by neutrinos.
Upper and lower cosmological limits on neutrino mass are derived. The role that
neutrinos may play in formation of large scale structure of the universe is
described and neutrino mass limits are presented. Effects of neutrinos on
cosmological background radiation and on big bang nucleosynthesis are
discussed. Limits on the number of neutrino flavors and mass/mixing are given.Comment: 41 page, 7 figures; lectures presented at ITEP Winter School,
February, 2002; to be published in the Proceeding
Antimatter in the Universe
Cosmological models which predict a large amount of antimatter in the
Universe are reviewed. Observational signatures and searches for cosmic
antimatter are briefly considered. A short discussion of new long range forces
which might be associated with matter and antimatter is presented.Comment: 17 pages + 2 figure
Scalar Electrodynamics and Primordial Magnetic Fields
A primordial magnetic field may be generated during an inflationary period if
conformal invariance is broken. We reexamine and generalize previous results
about the magnetic field produced by couplings of the form . We show that the amplitude of the magnetic field depends
strongly on . For adequate values of the field produced can serve as
seed for galactic magnetic fields. We also compute the effective interaction
between the electromagnetic field and the geometry in the context of scalar QED
(with and without classical conformal invariance). In both cases, the amplitude
of the magnetic field is too small to be of astrophysical interest.Comment: 16 pages, LaTeX, no figure
Neutrino flavor conversion in a neutrino background: single- versus multi-particle description
In the early Universe, or near a supernova core, neutrino flavor evolution
may be affected by coherent neutrino-neutrino scattering. We develop a
microscopic picture of this phenomenon. We show that coherent scattering does
not lead to the formation of entangled states in the neutrino ensemble and
therefore the evolution of the system can always be described by a set of
one-particle equations. We also show that the previously accepted formalism
overcounts the neutrino interaction energy; the correct one-particle evolution
equations for both active-active and active-sterile oscillations contain
additional terms. These additional terms modify the index of refraction of the
neutrino medium, but have no effect on oscillation physics.Comment: 12 pages, 3 figures, minor typos correcte
Energy composition of the Universe: time-independent internal symmetry
The energy composition of the Universe, as emerged from the Type Ia supernova
observations and the WMAP data, looks preposterously complex, -- but only at
the first glance. In fact, its structure proves to be simple and regular. An
analysis in terms of the Friedmann integral enables to recognize a remarkably
simple time-independent covariant robust recipe of the cosmic mix: the
numerical values of the Friedmann integral for vacuum, dark matter, baryons and
radiation are approximately identical. The identity may be treated as a
symmetry relation that unifies cosmic energies into a regular set, a quartet,
with the Friedmann integral as its common genuine time-independent physical
parameter. Such cosmic internal (non-geometrical) symmetry exists whenever
cosmic energies themselves exist in nature. It is most natural for a finite
Universe suggested by the WMAP data. A link to fundamental theory may be found
under the assumption about a special significance of the electroweak energy
scale in both particle physics and cosmology. A freeze-out model developed on
this basis demonstrates that the physical nature of new symmetry might be due
to the interplay between electroweak physics and gravity at the cosmic age of a
few picoseconds. The big `hierarchy number' of particle physics represents the
interplay in the model. This number quantifies the Friedmann integral and gives
also a measure to some other basic cosmological figures and phenomena
associated with new symmetry. In this way, cosmic internal symmetry provides a
common ground for better understanding of old and recent problems that
otherwise seem unrelated; the coincidence of the observed cosmic densities, the
flatness of the co-moving space, the initial perturbations and their amplitude,
the cosmic entropy are among them.Comment: 32 page
Neutrino statistics and non-standard commutation relations
Recently it was suggested that the neutrino may violate the Pauli exclusion
Principle (PEP). This renews interest in the systematic search for bilinear
commutation relations that could describe deviations from PEP. In the context
of this search we prove a no-go theorem which forbids a finite occupancy limit
for an arbitrary system with a bilinear commutation relation. In other words,
either the upper limit on the occupancy number is 1 (the ordinary fermionic
case) or there is no upper limit at all. Some examples of the latter class
include the usual Bose statistics, as well as non-standard quon statistics and
infinite statistics.Comment: 11 pages, RevTeX
Биологическая оценка меда
The article shows the results of the use of ciliates Tetrahymena pyriformis, for biological evaluation of honey. It is known that ciliates Tetrahymena pyriformis, similar in general characteristics of metabolism with higher animals, can serve as sufficient testing organism during biological evaluation of honey which is a good nutrient substrate for these simple. The main criteria of harmlessness and biological usefulness of honey is its growth promoting effect which is appliable to ciliates Tetrahymena pyriformis.В статье приведены результаты использования инфузорий Tetrahymena pyriformis для биологической оценки меда
On the variation of the gauge couplings during inflation
It is shown that the evolution of the (Abelian) gauge coupling during an
inflationary phase of de Sitter type drives the growth of the two-point
function of the magnetic inhomogeneities. After examining the constraints on
the variation of the gauge coupling arising in a standard model of inflationary
and post-inflationary evolution, magnetohydrodynamical equations are
generalized to the case of time evolving gauge coupling. It is argued that
large scale magnetic fields can be copiously generated. Other possible
implications of the model are outlined.Comment: 5 pages in RevTex style, one figur
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