The puzzle of composition of cosmic rays with energies (2-12.5) EeV according to muon detectors data of the Yakutsk EAS array

TL;DR

This study analyzes cosmic ray composition in the 2-12.5 EeV energy range using muon detector data from the Yakutsk array, identifying four distinct groups of primary particles to enhance understanding of cosmic ray origins.

Contribution

It introduces a muon correlation method applied to a long-term dataset to distinguish four primary particle groups in cosmic rays within the specified energy range.

Findings

Confirmed existence of four primary particle groups.

Identified potential origins for different cosmic ray groups.

Provided insights into cosmic ray composition at ultra-high energies.

Abstract

The results of a study of the cosmic ray composition in individual events in the energy range (2-12.5) EeV using the muon correlation method is presented. The considered sample included showers with zenith angles less than 60 degrees recorded in the period 1974-2018. The existence of four separate groups of primary particles with different origins is confirmed. The obtained results have potential importance for understanding the composition of cosmic rays in the specified primary energy range.