R. I. Raikin

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.

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.

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.

Lateral distribution of electrons in air showers

We investigate the lateral distribution of electrons in extensive air showers generated by 10 5 ÷10 9 GeV protons. It was found that the lateral distribution function in extensive air showers contains the same invariant part as the one in a pure electromagnetic cascade. This scaling property is poorly sensitive to the variation of basic. parameters of the hadron-nucleus interactions model. We also report on some initial results obtained for the description of the transition effect of shower particles within scintillators of different thickness.

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

Results from calculating the cosmic ray energy spectrum within the Galactic origin scenario are presented. Key elements of the approach are the assumed existence of Galactic sources that accelerate particles up to ∼1011 GeV and a highly inhomogeneous (fractal type) distribution of matter and magnetic fields in the Galaxy that leads to large free paths for particles (Levy flights), along with an overwhelming contribution to the cosmic ray fluxes observed in the energy range of 109–1011 GeV from particles reaching the Solar System without scattering. It is shown that the proposed scenario allows us to describe the main features of the observed cosmic ray spectrum from 1010 to 1020 eV. The behavior of the cosmic ray mass composition in the ultra-high energy region is discussed.

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

A new approach to deducing the mass composition of primary cosmic rays is proposed using the air showers universality and the scaling property of the electron lateral distribution function. Experimental data from the KASCADE, MSU, and KASCADE-Grande arrays have been analyzed, allowing conclusions as to the variations of mass composition above the knee to be drawn independently of the hadron-nucleus interaction model.

Air shower universality in the energy range of 1014 to 1022 eV

Universality in the development of air showers initiated by photons and the nuclei of cosmic rays is studied over a wide range of energies (1014–1022 eV). The scaling invariance of the lateral distribution of electrons and the universal relationship between a cascade’s age and radial scaling parameter (the root-meansquare radius of the electron component) are found to remain valid up to ultimate high energies with allowance for the Landau-Pomeranchuk-Migdal effect and interaction with the geomagnetic field. Possible applications of universality for matching, reanalyzing, and verifying the validity of data from different experiments, and for reducing the effect of the nuclear interaction model’s uncertainty on estimates of the mass composition of primary cosmic rays, are discussed.

Model-stable universality of the air shower electromagnetic component: An approach to solving the mass composition problem

On the basis of the scaling approach and CORSIKA simulations data the radial scale factor of lateral distribution of electrons in extensive air showers is confir med as potentially e ffective primary mass estimator, and its sensitivity to hadronic interaction model is invest igated. It is shown that improved composition results both on average and event-by-event basis can be achieved tak ing into account the universality property of air shower development expressed by the relation between radia l scale factor and longitudinal age parameter. The enhancements of such a theoretically motivated tool for the unbiased cosmic ray composition deduction in a wide primary energy range from (multi-)hybrid air shower me asurements of nearest future are discussed.

Improving the accuracy of cosmic ray mass composition estimation using the scale factor of the electron lateral distribution in air showers

The prospects for using the scale factor of the lateral distribution of electrons in air showers as an indicator of the type of cosmic ray primary particle is studied. The developed approach allows to improve the accuracy of reconstructing the mass composition of high-energy cosmic radiation on both an average and event-by-event basis, along with the reanalysis and verification of the congruence between data from different experiments and their cross-calibration and validation. The problem of estimating the scale factor of the electron lateral distribution using data from existing EAS arrays in light of their prospective upgrading is discussed.

Spectra of protons and nuclei in the energy range of 1010 ÷ 1020 eV in the framework of Galactic cosmic ray origin

We consider the problem of the cosmic ray spectrum formation assuming that cosmic rays are produced by Galactic sources. The anomalous diffusion equation proposed in our recent papers is used to describe cosmic ray propagation in the interstellar medium. We show that in the framework of this approach and with generation spectrum exponent