256 research outputs found
Lateral-angular and temporal characteristics of EAS optical radiation
Characteristics of the direct and scattered components of electron-photon shower optical radiation for distances R 500 m from the shower core to a detector, allowing for the Cerenkov and fluorescent mechanism of photon generation are presented. The results of calculations are employed to clarify the techniques for determination of the shower parameters detected by both installations registering fluorescent light and those recording Cerenkov light
Deterministic growth model of Laplacian charged particle aggregates
The results of the computer simulation of the aggregates growth of the
similarly charged particles in the framework of deterministic Laplacian growth
model on a square lattice are presented. Cluster growth is controlled by three
parameters , where - Laplacian growth parameter, -
energy of a particle sticking to a cluster, - the screening length of
electrostatic interactions. The phase diagram of cluster growth is built in the
co-ordinates . The zones of different cluster morphology are
selected: I-the zone of finite X-like structures,II-the zone of infinite
ramified structures, controlled by electrostatic interactions, III-the zone of
infinite structures with electrostatic interactions effectively switched off.
Simple electrostatic estimations of the locations of the zone boundaries are
presented. It is shown that in general case within the zone II the continuous
change of , controlled by parameters , takes place. In the
degeneration limit when the given model transforms into deterministic version
of the Eden model (at ), the crossover from linear to compact
structures is observed when passing through the boundary between the
zones I and II.Comment: REVTEX, 3 pages with 4 postscript figure
Integral functions of electron lateral distribution and their fluctuations in electron-photon cascades
Monte Carlo simulated lateral distribution functions for electrons of EPC developing in lead, at superhigh energies (.1-1 PeV) for depths t or = 60 c.u. delta t=1t. c.u. are presented. The higher moment characteristics, i.e., variation, asymmetry, excess, are presented along with analytical solutions for the same characteristics at fixed observation level calculated to theory approximations A and B by using numerical inversion of the Laplace transformation. The conclusion is made of a complex, usually non-Gaussian shape of the function of the particle number distribution within a circle of given radius at fixed depth
Sensitivity of depth of maximum and absorption depth of EAS to hadron production mechanism
Comparison of experimental data on depth of extensive air showers (EAS) development maximum in the atmosphere, T sub M and path of absorption, lambda, in the lower atmosphere of EAS with fixed particle number in the energy region eV with the results of calculation show that these parameters are sensitive mainly to the inelastic interaction cross section and scaling violation in the fragmentation and pionization region. The data are explained in a unified manner within the framework of a model in which scaling is violated slightly in the fragmentation region and strongly in the pionization region at primary cosmic rays composition close to the normal one and a permanent increase of inelastic interaction cross section. It is shown that, while interpreting the experimental data, disregard of two methodical points causes a systematic shift in T sub M: (1) shower selection system; and (2) EAS electron lateral distribution when performing the calculations on basis of which the transfer is made from the Cerenkov pulse FWHM to the depth of shower maximum, T sub M
Instanton dominance of topological charge fluctuations in QCD?
We consider the local chirality of near-zero eigenvectors from Wilson-Dirac
and clover improved Wilson-Dirac lattice operators as proposed recently by
Horv\'ath et al. We studied finer lattices and repaired for the loss of
orthogonality due to the non-normality of the Wilson-Dirac matrix. As a result
we do see a clear double peak structure on lattices with resolutions higher
than 0.1 fm. We found that the lattice artifacts can be considerably reduced by
exploiting the biorthogonal system of left and right eigenvectors. We conclude
that the dominance of instantons on topological charge fluctuations is not
ruled out by local chirality measurements.Comment: 10 pages, 6 figure
Shape of primary proton spectrum in multi-TeV region from data on vertical muon flux
It is shown, that primary proton spectrum, reconstructed from sea-level and
underground data on muon spectrum with the use of QGSJET 01, QGSJET II, NEXUS
3.97 and SIBYLL 2.1 interaction models, demonstrates not only model-dependent
intensity, but also model-dependent form. For correct reproduction of muon
spectrum shape primary proton flux should have non-constant power index for all
considered models, except SIBYLL 2.1, with break at energies around 10-15 TeV
and value of exponent before break close to that obtained in ATIC-2 experiment.
To validate presence of this break understanding of inclusive spectra behavior
in fragmentation region in p-air collisions should be improved, but we show,
that it is impossible to do on the basis of the existing experimental data on
primary nuclei, atmospheric muon and hadron fluxes.Comment: Submitted to Phys. Rev.
On the biological role of Fraunhofer lines of the Sun
The important role of Fraunhofer lines formed in the solar atmosphere in the spectrum of the Sun for the biological evolution on Earth has been discussed. In vitro, laboratory experiments have been accomplished to substantiate the concept of the role of Fraunhofer lines as drivers of the evolution via impact on molecules of biological significance. As a practical application of the concept,
successful results of clinical tests on humans have been obtained to demonstrate the possibility of non-medicinal means to be used for therapy in the cases of infectious
deceases such as HIV/AIDS. The importance for human health of blurring Fraunhofer lines due to increasing atmospheric pollution has been emphasized
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