10 research outputs found
Features of Muon Arrival Time Distributions of High Energy EAS at Large Distances From the Shower Axis
In view of the current efforts to extend the KASCADE experiment
(KASCADE-Grande) for observations of Extensive Air Showers (EAS) of primary
energies up to 1 EeV, the features of muon arrival time distributions and their
correlations with other observable EAS quantities have been scrutinised on
basis of high-energy EAS, simulated with the Monte Carlo code CORSIKA and using
in general the QGSJET model as generator. Methodically various correlations of
adequately defined arrival time parameters with other EAS parameters have been
investigated by invoking non-parametric methods for the analysis of
multivariate distributions, studying the classification and misclassification
probabilities of various observable sets. It turns out that adding the arrival
time information and the multiplicity of muons spanning the observed time
distributions has distinct effects improving the mass discrimination. A further
outcome of the studies is the feature that for the considered ranges of primary
energies and of distances from the shower axis the discrimination power of
global arrival time distributions referring to the arrival time of the shower
core is only marginally enhanced as compared to local distributions referring
to the arrival of the locally first muon.Comment: 24 pages, Journal Physics G accepte
Cosmic ray spectrum and anisotropies from the knee to the second knee
We consider the scenario in which the knee in the cosmic ray spectrum is due
to a change in the escape mechanism of cosmic rays from the Galaxy from one
dominated by transverse diffusion to one dominated by drifts. We show that this
scenario explains not only the changes in spectral slope at the knee and at the
second knee, but can also account for the main characteristics of the observed
energy dependent anisotropy amplitude and phase of first harmonic in the energy
range between and eV. This provides a useful handle to
distinguish this diffusion/drift model from other scenarios proposed to explain
the knee in the spectrum.Comment: 13 pages, 3 figures; revised version with minor changes. To appear in
JCA
Rigidity dependent knee and cosmic ray induced high energy neutrino fluxes
Scenarios in which the knee of the cosmic ray spectrum depends on the
particle rigidities usually predict that the cosmic ray composition becomes
heavier above the knee and have associated a change in the spectral slope of
each individual nuclear component which is steeper than the change
() observed in the total spectrum. We show that this
implies that the very high energy ( eV) diffuse neutrino fluxes
produced by cosmic rays hitting the atmosphere or colliding with the
interstellar medium in the Galaxy will be significantly suppressed, making
their detection harder but also reducing the background for the search of other
(more challenging) astrophysical neutrino sources.Comment: 20 pages, 5 figure
KASCADE-Grande Limits on the Isotropic Diffuse Gamma-Ray Flux between 100 TeV and 1 EeV
KASCADE and KASCADE-Grande were multi-detector installations to measure
individual air showers of cosmic rays at ultra-high energy. Based on data sets
measured by KASCADE and KASCADE-Grande, 90% C.L. upper limits to the flux of
gamma-rays in the primary cosmic ray flux are determined in an energy range of
eV. The analysis is performed by selecting air showers
with a low muon content as expected for gamma-ray-induced showers compared to
air showers induced by energetic nuclei. The best upper limit of the fraction
of gamma-rays to the total cosmic ray flux is obtained at eV with . Translated to an absolute gamma-ray
flux this sets constraints on some fundamental astrophysical models, such as
the distance of sources for at least one of the IceCube neutrino excess models.Comment: Published in The Astrophysical Journal, Volume 848, Number 1. Posted
on: October 5, 201
Test of Hadronic Interaction Models in the Forward Region with KASCADE Event Rates
An analysis of muon and hadron rates observed in the central detector of the
KASCADE experiment has been carried out. The data are compared to CORSIKA
simulations employing the high-energy hadronic interaction models QGSJET,
DPMJET, HDPM, SIBYLL, and VENUS. In addition, first results with the new
hadronic interaction model neXus 2 are discussed. Differences of the model
predictions, both among each other and when confronted with measurements, are
observed. The hadron rates mainly depend on the inelastic cross-section and on
the contribution of diffraction dissociation. The discrepancy between
simulations and measurements at low primary energies around 5 TeV can be
reduced by increasing the non-diffractive part of the inelastic cross-section
of nucleon-air interactions. Examination of hadron multiplicities points
towards harder spectra of secondary pions and kaons needed in the calculations.Comment: 14 pages, 7 figures, corresponding author: M. Risse, accepted for
publication in J. Phys. G: Nucl. Part. Phy
Muon content in air showers between 10 PeV and 11EeV determined from measurements with2KASCADE-Grande
Probing the evolution of the EAS muon content in the atmosphere with KASCADE-Grande
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