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Attraction And Repulsion Of Multi-Color Laser Beams In Plasmas: A Computational Study
The nonlinear interaction of high-power multi-color laser beams in plasmas is investigated numerically. Both the relativistic mass increase and the driven plasma wave contribute to the mutual beam-beam interaction and to the development of the electromagnetic cascade. The propagation of the individual cascade sidebands is modelled in the paraxial approximation. The resulting set of coupled nonlinear envelope equations is solved numerically using a newly developed pseudospectral method. We predict that two beams intersecting in the plasma can either attract or deflect each other depending on whether their frequency detuning is slightly below or above the electron Langmuir frequency.Physic
Fluctuations of Xmax and Primary Particle Mass Composition in the Range of Energy 5 10^{17} - 3 10^{19} ev by Yakutsk Data
The experimental distributions of \Xmax obtained with the Yakutsk EAS array
at fixed energies of , and
eV are analysed. A recent version of the QGSJET model is used as a tool of our
analysis. In the framework of this model, the most adequate mass composition of
primary particles satisfying the experimental data on \Xmax is selected.Comment: 19th European Cosmic Ray Symposium, Aug 30 - Sep 3 2004, Florence,
Italy. 3 pages, 1 figure. Submitted for publication in International Journal
of Modern Physics
Hunting long-lived gluinos at the Pierre Auger Observatory
Eventual signals of split sypersymmetry in cosmic ray physics are analyzed in
detail. The study focusses particularly on quasi-stable colorless R-hadrons
originating through confinement of long-lived gluinos (with quarks,
anti-quarks, and gluons) produced in pp collisions at astrophysical sources.
Because of parton density requirements, the gluino has a momentum which is
considerable smaller than the energy of the primary proton, and so production
of heavy (mass ~ 500 GeV) R-hadrons requires powerful cosmic ray engines able
to accelerate particles up to extreme energies, somewhat above 10^{13.6} GeV.
Using a realistic Monte Carlo simulation with the AIRES engine, we study the
main characteristics of the air showers triggered when one of these exotic
hadrons impinges on a stationary nucleon of the Earth atmosphere. We show that
R-hadron air showers present clear differences with respect to those initiated
by standard particles. We use this shower characteristics to construct
observables which may be used to distinguish long-lived gluinos at the Pierre
Auger Observatory.Comment: 13 pages revtex, 9 eps figures. A ps version with high resolution
figures is available at
http://www.hep.physics.neu.edu/staff/doqui/rhadron_highres.p
Study of the efficiency use of physical rehabilitation in patients with chronic gastritis
Purpose: to make physical rehabilitation program for patients with chronic gastritis type B, promotes normalization of gastric secretory function and prolong the period of remission. Objectives of the study was to assess the dynamics of gastric secretory function and functional status of the autonomic nervous system in patients with the chronic gastritis type B . Material: the study involved 37 women with a diagnosis of the chronic gastritis type B, increased acid gastric function. Results: it was established the positive influence of corrective exercises for the lower thoracic and lumbar spine, regulated breathing exercises based on the tone of the autonomic nervous system in combination with massage and diet therapy on the state of gastric secretory function. Conclusions : it is recommended to carry out therapeutic physical culture in the form of morning hygienic gymnastics, therapeutic exercises, self-study
Lateral distribution of high energy muons in EAS of sizes Ne approximately equals 10(5) and Ne approximately equals 10(6)
Muon energy spectra and muon lateral distribution in EAS were investigated with the underground magnetic spectrometer working as a part of the extensive air showers (EAS) array. For every registered muon the data on EAS are analyzed and the following EAS parameters are obtained, size N sub e, distance r from the shower axis to muon, age parameter s. The number of muons with energy over some threshold E associated to EAS of fixed parameters are measured, I sub reg. To obtain traditional characteristics, muon flux densities as a function of the distance r and muon energy E, muon lateral distribution and energy spectra are discussed for hadron-nucleus interaction model and composition of primary cosmic rays
The Affine-Metric Quantum Gravity with Extra Local Symmetries
We discuss the role of additional local symmetries related to the
transformations of connection fields in the affine-metric theory of gravity.
The corresponding BRST transformations connected with all symmetries (general
coordinate, local Lorentz and extra) are constructed. It is shown, that extra
symmetries give the additional contribution to effective action which is
proportional to the corresponding Nielsen-Kallosh ghost one. Some arguments are
given, that there is no anomaly associated with extra local symmetries.Comment: 14 pages in LATEX (The version of paper accepted for publication in
Class. Quant. Grav.
Depth of maximum of extensive air showers and cosmic ray composition above 10**17 eV in the geometrical multichain model of nuclei interactions
The depth of maximum for extensive air showers measured by Fly's Eye and
Yakutsk experiments is analysed. The analysis depends on the hadronic
interaction model that determine cascade development. The novel feature found
in the cascading process for nucleus-nucleus collisions at high energies leads
to a fast increase of the inelasticity in heavy nuclei interactions without
changing the hadron-hadron interaction properties. This effects the development
of the extensive air showers initiated by heavy primaries. The detailed
calculations were performed using the recently developed geometrical multichain
model and the CORSIKA simulation code. The agreement with data on average depth
of shower maxima, the falling slope of the maxima distribution, and these
distribution widths are found for the very heavy cosmic ray mass spectrum
(slightly heavier than expected in the diffusion model at about 3*10**17 eV and
similar to the Fly's Eye composition at this energy).Comment: 11pp (9 eps figures
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