The knee in the primary-cosmic-ray spectrum, observed in the hadron component of extensive-air-shower cores at the mountain level
The spectra of the hadron component in extensive-air-shower (EAS) cores detected at the Tien Shan high-altitude scientific station of the Lebedev Institute of Physics, Russian Academy of Sciences, have been analyzed. Simulation was performed using the CORSIKA code within the QGSJET01 and QGSJET02 models under different assumptions about the primary-cosmic-ray (PCR) spectrum in the knee region. It is shown that the QGSJET01 model underestimates the energy of the hadron component of EAS cores at the mountain level. It is also shown that a pronounced knee in the experimental spectrum suggests a sharp (dγ ∼ 1.5) change in the exponent of the proton spectrum slope at an energy of about 5 PeV.