14850539
About EAS inverse approach
It is shown that using the observed extensive air shower (EAS) electron and truncated muon size spectra at sea level one can solve the EAS inverse problem - reconstruction of primary energy spectra and elemental composition, for not more than 2 kinds of primary nuclei.
15765199
About EAS size spectra and primary energy spectra in the knee region
Based on the unified analyses of KASCADE, AKENO, EAS-TOP and ANI EAS size spectra, the approximations of energy spectra of different primary nuclei have been found. Calculations were carried out using SIBYLL and QGSJET interaction models in 0.1-100 PeV primary energy range. The results point to existence of both rigidity-dependent steepening energy spectra at R=200-400 TV and an additional proton (neutron) component with differential energy spectrum (6.1+/-0.7)10^{-11}(E/Ek)^{-1.5} (m^2.s.sr.TeV)^{-1} before the knee Ek=2030+/-130 TeV and with power index g2=-3.1+/-0.05 after the knee.
125873936
A Program for investigation of the muon component in EAS on the magnetic spectrometer ANI in the energy range from 5-GeV to 3000-GeV
103336904
Calibration of energy measured in Roentgen emulsion experiments. (In Russian)
117993503
Search Capability for eta ---> nu(e, tau) anti-nu(e, tau) Decays in Cubic Kilometer Neutrino Detectors
We investigate the discovery potential of cubic-kilometer neutrino observatories such as IceCube to set stringent limits on the forbidden decays η → v e v e and η → v τ v τ . The signatures for these decays are cascade events resulting from the charged-current reactions of v e , v τ , v e , and v τ on nuclei in such detectors. Background cascade events are mainly due to v e 's from atmospheric μ, K + , and K 0 S decays and to a lesser extent from atmospheric v μ neutral-current interactions with nuclei. A direct upper limit for the branching ratio η → v e,τ v e,τ of 6.1 × 10 -4 at 90% CL can be achieved.
14618248
Anisotropy analysis of EAS data in the knee region
Based on MAKET-ANI EAS data the distributions of equatorial coordinates of EAS core directions are obtained in the knee region. Anisotropy of primary cosmic rays is displayed only by declination equatorial coordinates (20+/-3 degrees) at primary energies more than 5-10 PeV. The fraction of anisotropic component turns out ~10% in the knee region.
17568500
An all-particle primary energy spectrum in the 3–200 PeV energy range
We present an all-particle primary cosmic-ray energy spectrum in the 3 × 10 6 – 2 × 10 8 GeV energy range obtained by a multi-parametric event-by-event evaluation of the primary energy. The results are obtained on the basis of an expanded EAS data set detected at mountain level (700 g cm −2 )b y the GAMMA experiment. The energy evaluation method has been developed using the EAS simulation with the SIBYLL interaction model taking into account the response of GAMMA detectors and reconstruction uncertainties of EAS parameters. Nearly unbiased (<5%) energy estimations regardless of a primary nuclear mass with an accuracy of about 15–10% in the 3 × 10 6 –2 × 10 8 GeV energy range respectively are attained. An irregularity (‘bump’) in the spectrum is observed at primary energies of ∼7.4 × 10 7 GeV. This bump exceeds a smooth power-law fit to the data by about 4 standard deviations. By not rejecting the stochastic nature of the bump completely, we examined the systematic uncertainties of our methods and conclude that they cannot be responsible for the observed feature.
118825755
Alternative description of particle shower longitudinal profile
An alternative parametrization of the particle shower longitudinal profile is presented. The accuracy of the obtained shower profile description is about 2-3% for the 0-1500 g/cm^2 atmosphere slant depths and primary H, He,... Fe nuclei in the 1 PeV-10 EeV energy range. It is shown that the shape of shower profile depends only on the nucleon energy, whereas the maximum shower size also depends on the energy of the parental nucleus. Results are based on the CORSIKA simulated shower profiles and are presented in comparison with the Gaisser-Hillas parametrization.
118459803
Sharp knee phenomenon of primary cosmic ray energy spectrum
Primary energy spectral models are tested in the energy range of 1-200 PeV using standardized extensive air shower responses from BASJE-MAS, Tibet, GAMMA and KASCADE scintillation shower arrays. Results point towards the two-component origin of observed cosmic ray energy spectra in the knee region (GAPS spectral model) consisting of a pulsar component superimposed upon rigidity-dependent power law diffuse galactic flux. The two-component energy spectral model accounts for both the sharp knee shower spectral phenomenon and observed irregularity of all-particle energy spectrum in the region of 50-100 PeV. Alternatively, tested multi-population primary energy spectra predicted by non-linear diffusive shock acceleration (DSA) models describe observed shower spectra in the knee region provided that the cutoff magnetic rigidities of accelerating particles are 6.0+/-0.3 PV and 45+/-2 PV for the first two populations respectively. Both tested spectral models confirm the predominant H-He primary nuclei origin of observed shower spectral knee. The parameters of tested energy spectra are evaluated using solutions of inverse problem on the basis of the corresponding parameterizations of energy spectra for primary H, He, O-like and Fe-like nuclei, standardized shower size spectral responses in the 550-1085 g/cm^2 atmospheric slant depth range and near vertical muon truncated size spectra detected by the GAMMA array.
15964309
Mutually compensative pseudo solutions of primary energy spectra in the knee region
Abstract The problem of the uniqueness of solutions during the evaluation of primary energy spectra in the knee region using an extensive air shower (EAS) data set and the EAS inverse approach is investigated. It is shown that the unfolding of primary energy spectra in the knee region leads to mutually compensative pseudo solutions. These solutions may be the reason for the observed disagreements in the elementary energy spectra of cosmic rays in the 1–100 PeV energy range obtained from different experiments.
118956991
Primary Energy Spectra and Elemental Composition. GAMMA Experiment
On the basis of the Extensive Air Shower data observed by the GAMMA experiment the energy spectra and elemental composition of the primary cosmic rays have been derived in the 1-100 PeV energy range. Reconstruction of the primary energy spectra is carried out in the framework of the SIBYLL and QGSJET interaction models and the hypothesis of the power-law steepening primary energy spectra. All presented results are derived taking into account the detector response, reconstruction uncertainties of EAS parameters and fluctuation of EAS development.