Comparing the energy spectra of ultra-high energy cosmic rays measured with EAS arrays

TL;DR

This paper investigates discrepancies in ultra-high energy cosmic ray spectra measured by EAS arrays, identifying systematic errors and applying correction factors to reconcile differences, supporting models of cosmic ray origin transition.

Contribution

It introduces correction factors for surface array measurements to resolve spectral discrepancies and confirms consistency with cosmic ray transition models.

Findings

Corrected energy spectra align within experimental errors.

Residual differences are due to detection technique accuracy.

CR models agree with observed spectra.

Abstract

The energy spectra of ultra-high energy cosmic rays (CRs) measured with giant extensive air shower (EAS) arrays exhibit discrepancies between the flux intensities and/or estimated CR energies exceeding experimental errors. The well-known intensity correction factor due to the dispersion of the measured quantity in the presence of a rapidly falling energy spectrum is insufficient to explain the divergence. Another source of systematic energy determination error is proposed concerning the charged particle density measured with the surface arrays, which arises due to simplifications (namely, the superposition approximation) in nucleus-nucleus interaction description applied to the shower modeling. Making use of the essential correction factors results in congruous CR energy spectra within experimental errors. Residual differences in the energy scales of giant arrays can be attributed to the actual overall accuracy of the EAS detection technique used. CR acceleration and propagation model simulations using the dip and ankle scenarios of the transition from galactic to extragalactic CR components are in agreement with the combined energy spectrum observed with EAS arrays.