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VOLUME 87 (2008) | ISSUE 4 |
PAGE 220
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Muon content of ultra-high-energy air showers: Yakutsk data versus simulations
A. V. Glushkov, I. T. Makarov1), M. I. Pravdin1), I. E. Sleptsov1), D. S. Gorbunov*, G. I. Rubtsov*, S. V. Troitsky*
PACS: 13.85.Tp, 98.70.Sa
Abstract
We analyse a sample of 33 extensive air showers (EAS) with estimated
primary energies above 2• 1019 eV and high-quality muon data
recorded by the Yakutsk EAS array. We compare, event-by-event, the
observed muon density to that expected from CORSIKA simulations for
primary protons and iron, using SIBYLL and EPOS hadronic interaction
models. The study suggests the presence of two distinct hadronic
components, "light" and "heavy".
Simulations with EPOS are in a good
agreement with the expected composition in which the light component
corresponds to protons and the heavy component to iron-like nuclei.
With SYBILL, simulated muon densities for iron primaries are a factor of
less than those observed for the heavy component, for the same
electromagnetic signal.
Assuming two-component proton-iron composition and the EPOS model, the
fraction of protons with energies
E>1019 eV is 0.52 +0.19-0.20 at 95% confidence level.
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