MUONS WITH Eth ≥ 1 GEV AND MASS COMPOSITION IN THE ENERGY RANGE 10 18 − 10 20 EV OBSERVED BY YAKUTSK EAS ARRAY

• Main Authors: S. P. Knurenko, V. A. Kolosov, I. T. Makarov, I. Ye. Sleptsov, V. R. Sleptsova, G. G. Struchkov
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2004
• Subjects: Eth = 1 GeV × sec(θ; Yakutsk
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.255.3073; http://arxiv.org/pdf/astro-ph/0411683v2.pdf

The ratio of the muon flux density to charged particle flux density at distances of 300 and 600 m from the shower axis (ρµ(300)/ρs(300) and ρµ(600)/ρs(600)) is measured. In addition, the energy dependence of ρµ(1000) is analysed for showers with energies above 10 18 eV. A comparison between the experimental data and calculations performed with the QGSJET model is given for the cases of primary proton, iron nucleus and gamma- ray. We conclude that the showers with E0 ≥ 3 × 10 18 eV can be formed by light nuclei with a pronounced fraction of protons and helium nuclei. It is not excluded however that a small part of showers with energies above 10 19 eV could be initiated by primary gamma-rays.