On the Problem of Ultrahigh Energy Cosmic Ray Mass Composition Evaluation from Lateral Distributions of EAS Charged Particles Measured at Different Ranges of Radial Distances

Abstract

The results of the analysis of simulations of extensive air showers (EAS) generated by ultrahigh energy cosmic rays are presented. The analysis was performed within the framework of the scaling approach developed by the authors to describe the lateral distribution functions of electrons and muons of EAS. We discuss a method to evaluate the mass composition of cosmic rays from the experimental data of existing ground-based hybrid experiments with consideration of the potential of their forthcoming extensions as well as the next generation experiments. The discussed method allows minimizing the influence of the uncertainty of nuclear interaction model, instrumental and methodical biases on physical conclusions with respect to the type of primary particle.
 It is shown that the use of the scale parameters of the lateral distributions as an indicator of primary particle, as well as the universal relationship between the scale parameters of the lateral distribution and the (longitudinal) age of the cascade, provides improving mass composition estimations on both the average and event-by-event basis by a single method in a wide primary energy range.