Content of muons in extensive air showers measured by Yakutsk array

TL;DR

This study analyzes muon distributions in extensive air showers at Yakutsk, comparing measurements before and after detector upgrades, and evaluates cosmic ray composition above 10^18 eV using different models.

Contribution

It provides a detailed comparison of muon densities with hadron interaction models and assesses primary cosmic ray composition at ultra-high energies.

Findings

Muon densities align best with proton primary models above 10^18 eV.

Detector upgrades improved measurement accuracy.

Proton composition is favored for primary cosmic rays at high energies.

Abstract

Lateral distribution of muons in extensive air showers registered at the Yakutsk array was investigated. The analysis covers two periods of observation: before 2018 and after 2020, when the revision of muon detectors with 1-GeV threshold was complete. Measured values of muon density are compared to computational results obtained within the framework of two hadron interaction models. Within the energy domain above $10^{18}$ eV the best agreement is observed for proton composition primary cosmic rays.