A. A. Lagutin

Lateral distribution of electrons in EAS at superhigh energies: predictions and experimental data

Abstract In this paper we present a new approximation for the lateral distribution function of electrons in extensive air showers based on the scaling property established in our recent works. The detailed comparisons of theoretical predictions for the lateral distribution of charged particles in EAS at superhigh energies obtained with the use of new LDF of electrons with the experimental data of AGASA and Yakutsk array are carried out. The influence of the scintillation detector response and the atmospheric temperature effect on the shape of the lateral distribution of electrons is discussed in brief.

On inconsistency of experimental data on primary nuclei spectra with sea level muon intensity measurements

For the first time a complete set of the most recent direct data on primary cosmic ray spectra is used as input into calculations of muon flux at sea level in a wide energy range E μ = 1 - (3 × 10 5 ) GeV. Computations have been performed with the CORSIKA/QGSJET and CORSIKA/VENUS codes. Comparison of the obtained muon intensity with the data of muon experiments shows that measurements of primary nuclei spectra conform to sea level muon data only up to several tens of GeV and result in essential deficit of muons at higher energies. As it follows from our examination, uncertainties in muon flux measurements and in the description of nuclear cascades development are not suitable to explain this contradiction, and the only remaining factor, leading to this situation, is underestimation of primary light nuclei fluxes. We have considered systematic effects, that may distort the results of the primary cosmic-ray measurements with the application of the emulsion chambers. We suggest, that re-examination of these measurements is required with the employment of different hadronic interaction models. Also, in our point of view, it is necessary to perform estimates of the possible influence of the fact that a sizable fraction of events, identified as protons, actually are antiprotons. Study of this cosmic-ray component begins to draw much attention, but today nothing definite is known for the energies >40 GeV. In any case, to realize whether the mentioned, or some other reasons are the sources of disagreement of the data on primaries with the data on muons, the indicated effects should be thoroughly analysed.

Electron lateral distribution in air showers: scaling formalism and its implications

Theoretical results representing further development of scaling formalism for the lateral distribution of electrons in atmospheric cascade showers are reported in this paper. A detailed study of the root mean square radius of extensive air shower electrons—the basic parameter of the lateral distribution function (LDF)—has been carried out. Comparisons of our predictions with CORSIKA simulation results and also KASCADE and AGASA experimental data are presented. A new method for cosmic ray primary composition deduction from the shape of electron LDF, applicable in wide primary energy range with weak sensitivity to hadronic interaction model, is introduced.

Energy spectrum and mass composition of primary cosmic rays around the 'knee' in the framework of the model with two types of sources

Analysis of the experimental data on cosmic ray spectra in the framework of the proposed model with two types of sources leads to conclusion, that sources with particle generation spectral exponent p ∼ 2.85 give the major contribution to the all-particle spectrum in the energy range 10 5 – 10 7 GeV . ‘Fine structure’ of spectrum around the ‘knee’ may arise due to presence of nearby supernova type source, accelerating particles up to the energies ∼ 3 ⋅ 10 4 Z GeV , if the energy output of such source is ∼ 2 ⋅ 10 48 erg/source .

Cosmic ray primary mass composition above the knee: deduction from lateral distribution of electrons

Influence of shower fluctuations on the shape of lateral distribution of electrons in EAS of fixed size measured by scintillation counters is analyzed in framework of scaling formalism. Correction factors for the mean square radius of electrons are calculated for the experimental conditions of KASCADE array. Possible improvement of the primary mass discrimination by analysis of lateral distribution of EAS electrons is discussed in detail.

Energy spectrum and mass composition of primary cosmic rays in the vicinity of the “knee” in a model with two types of sources

An analysis of the data on the spectra of cosmic rays in the context of the proposed model with two types of sources suggests that the main contribution to the spectrum of all particles in the range of 105−107 GeV is made by the sources in which the exponent in the spectrum of particles’ generation p ≈ 2.85. The complex structure of the spectrum in the vicinity of the “knee” may arise owing to the presence of an additional supernova-type source that accelerates the particles to the energies of ∼3 × 104Z GeV if the energy output of this source is ∼2 × 1048 erg/source.

Spectrum and fraction of cosmic ray positrons: results of the anomalous diffusion approach

We present the results of new calculations of the energy spectra of cosmic ray electrons, positrons and also positron fraction under assumption that both electrons and positrons are generated by the same Galactic sources, which accelerate particles with same power-law injection spectral index

Lateral distribution of electrons in air showers

p

Spectra of cosmic-ray protons and nuclei from 10 10 to 10 20 eV within the galactic origin scenario of cosmic rays

. The value of the injection index

Model-independent approach to deducing the mass composition of primary cosmic rays on the basis of the scale invariance in the radial distribution of electrons in extensive air showers

p\approx 2.85