Scaling violation in interaction of cosmic ray hadrons and the nature of the 3 PeV knee in the spectrum of primary cosmic rays

TL;DR

This study investigates the energy spectra of hadrons in extensive air showers, revealing a local spectral slope change and increased average hadron energy between 3 and 20 PeV, suggesting a connection to the cosmic ray spectrum knee.

Contribution

It provides the first direct measurement of a local spectral slope change in EAS hadrons and links this to the appearance of a penetrative component related to the cosmic ray knee.

Findings

Spectral slope of EAS hadrons diminishes between 3 and 20 PeV.

Average hadron energy increases in the same energy range.

Evidence supports an astrophysical origin of the penetrative component.

Abstract

Energy spectra of the most energetic hadrons in the core region of extensive air showers (EAS) were studied in dependence on the EAS energy $E_0$ in the hybrid experiment HADRON at the Tien Shan mountain cosmic ray station. For the first time by direct measurement it was found in this experiment that the slope of the power energy spectrum of EAS hadrons diminishes itself locally, and the average hadron energy, correspondingly, increases between the $E_0$ borders 3PeV and 20PeV. Such behavior agrees with threshold appearance in EAS, in the same energy range, of a long-flying penetrative component which was earlier revealed at the Tien Shan station. Now we reconsider this Tien Shan result in comparison with the new data of modern collider experiments. The analysis permits to state unambiguously an astrophysical nature of the penetrative EAS component, and to discuss its probable connection with the origin of the famous knee in the energy spectrum of cosmic rays at $E_0\simeq 3$ PeV.