Mass composition of cosmic rays with energy above 10**17 eV according to surface detectors of the Yakutsk EAS array

TL;DR

This study analyzes the lateral distribution of charged particles in extensive air showers with energies above 10^17 eV, using data from the Yakutsk array over several decades, and compares findings with theoretical models to infer cosmic ray composition.

Contribution

It provides a comprehensive comparison of experimental data with multiple hadron interaction models, identifying the best fits and observing a shift towards lighter cosmic ray composition at higher energies.

Findings

Best agreement with QGSJet models

Observed shift towards proton composition in (1-20) x 10^17 eV range

Data spans from 1977 to 2013

Abstract

We discuss the lateral distribution of charged particles in extensive air showers with energy above $10^{17}$ eV measured by surface scintillation detectors of Yakutsk EAS array. The analysis covers the data obtained during the period from 1977 to 2013. Experimental values are compared to theoretical predictions obtained with the use of CORSIKA code within frameworks of different hadron interaction models. The best agreement between theory and experiment is observed for QGSJet01 and QGSJet-II-04 models. A change in the cosmic ray mass composition towards proton is observed in the energy range $(1-20) \times 10^{17}$ eV.