686 research outputs found
One-loop corrections to the instanton transition in the two-dimensional Abelian Higgs model
We present an evaluation of the fluctuation determinant which appears as a
prefactor in the instanton transition rate for the two-dimensional Abelian
Higgs model. The corrections are found to change the rate at most by a factor
of 2 for 0.4 < M_W/M_H < 2.0.Comment: DO-TH-94/17, 20 pages, 4 figures appended as uucompressed .eps files,
LaTeX, needs epsfig.st
Pion Decay Constant at Finite Temperature in the Nonlinear Sigma Model
We calculate the pion decay constant near the critical temperature of the
nonlinear sigma model in the large limit. Making use of the known
low temperature behavior, we construct a Pad\'{e} approximant to obtain the
behavior of at all temperatures.Comment: 8 pages, one latex file and one postscript file (uses psfig).
Uuencode
Observational physics of mirror world
The existence of the whole world of shadow particles, interacting with each other and having no mutual interactions with ordinary particles except gravity is a specific feature of modern superstring models, being considered as models of the theory of everything. The presence of shadow particles is the necessary condition in the superstring models, providing compensation of the asymmetry of left and right chirality states of ordinary particles. If compactification of additional dimensions retains the symmetry of left and right states, shadow world turns to be the mirror one, with particles and fields having properties strictly symmetrical to the ones of corresponding ordinary particles and fields. Owing to the strict symmetry of physical laws for ordinary and mirror particles, the analysis of cosmological evolution of mirror matter provides rather definite conclusions on possible effects of mirror particles in the universe. A general qualitative discussion of possible astronomical impact of mirror matter is given, in order to make as wide as possible astronomical observational searches for the effects of mirror world, being the unique way to test the existence of mirror partners of ordinary particles in the Nature
Archimedean-type force in a cosmic dark fluid: II. Qualitative and numerical study of a multistage Universe expansion
In this (second) part of the work we present the results of numerical and
qualitative analysis, based on a new model of the Archimedean-type interaction
between dark matter and dark energy. The Archimedean-type force is linear in
the four-gradient of the dark energy pressure and plays a role of
self-regulator of the energy redistribution in a cosmic dark fluid. Because of
the Archimedean-type interaction the cosmological evolution is shown to have a
multistage character. Depending on the choice of the values of the model
guiding parameters,the Universe's expansion is shown to be perpetually
accelerated, periodic or quasiperiodic with finite number of
deceleration/acceleration epochs. We distinguished the models, which can be
definitely characterized by the inflation in the early Universe, by the
late-time accelerated expansion and nonsingular behavior in intermediate
epochs, and classified them with respect to a number of transition points.
Transition points appear, when the acceleration parameter changes the sign,
providing the natural partition of the Universe's history into epochs of
accelerated and decelerated expansion. The strategy and results of numerical
calculations are advocated by the qualitative analysis of the instantaneous
phase portraits of the dynamic system associated with the key equation for the
dark energy pressure evolution.Comment: 15 pages, 12 figures, Part II, typos corrected, Fig.4 replaced,
references correcte
Structure and three-body decay of Be resonances
The complex-rotated hyperspherical adiabatic method is used to study the
decay of low-lying Be resonances into one neutron and two
-particles. We investigate the six resonances above the break-up
threshold and below 6 MeV: , and . The
short-distance properties of each resonance are studied, and the different
angular momentum and parity configurations of the Be and He two-body
substructures are determined. We compute the branching ratio for sequential
decay via the Be ground state which qualitatively is consistent with
measurements. We extract the momentum distributions after decay directly into
the three-body continuum from the large-distance asymptotic structures. The
kinematically complete results are presented as Dalitz plots as well as
projections on given neutron and -energy. The distributions are
discussed and in most cases found to agree with available experimental data.Comment: 12 pages, 10 figures. To appear in Physical Review
Research Of Quality Indicators Of Protein-fat Mixture From Flax And Sesame Seeds For Nutrition Of Athletes
The aim of the research is to determine the microbiological stability of a protein-fat mixture of flax and sesame seeds that allows to correct its storage life. A protein-fat mixture has a high content of irreplaceable amino acids ВСАА and polyunsaturated fatty acids of w-3group, so it may be positioned as a component of nutrition for athletes. Flax and sesame seeds, cultivated in Ukraine, were used as research materials. The product was created, based on comminuted flax and sesame seeds in ratio 1:1. There were determined organoleptic (outlook, taste, smell, color) and physical-chemical (mass share of moisture, ash, protein, fat, acidic, peroxide, anisidine number) parameters of the product. There was determined the microbiological stability of the protein-fat mixture of the increased food value for athletes nutrition after 6 months. It has been proved, that as opposite to the control sample, the protein-fat mixture of the developed composition manifests its microbiological stability by the following parameters: content of mesophilic aerobic and facultative anaerobic microorganisms, molds, yeast, bacteria of the colon bacillus group and pathogenic microorganisms. The control sample that is comminuted flax seeds doesn\u27t manifest at the end of the storage term any correspondence of microbiological parameters by the content of mesophilic aerobic and facultative anaerobic microorganisms, molds, and bacteria of the colon bacillus group. This regularity is explained by the presence of lignans, sesamol and sesamoline, with preservative properties in the developed product. The obtained data may be used for reasoning recipes of products, based on the protein-fat mixture and correction of the food supplements ratio in them
The Zipf law for random texts with unequal probabilities of occurrence of letters and the Pascal pyramid
We model the generation of words with independent unequal probabilities of
occurrence of letters. We prove that the probability of occurrence of
words of rank has a power asymptotics. As distinct from the paper published
earlier by B. Conrad and M. Mitzenmacher, we give a brief proof by elementary
methods and obtain an explicit formula for the exponent of the power law.Comment: 4 page
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