Specific observables of extensive air showers, such as the depth of shower maximum and relative size of the air-shower muonic component, are sensitive to the mass of the primary cosmic-ray particle and therefore provide an avenue for cosmic-ray mass composition analyses.
The separation power between proton, helium, oxygen, and iron cosmic rays, on an event-by-event basis, was studied using exact knowledge of mass sensitive air-shower observables determined from CORSIKA simulations at the sites of the IceCube Neutrino Observatory at the South Pole and the Pierre Auger Observatory in Argentina.
The simulations cover shower energies from 10 PeV to a few EeV and a wide range of zenith angles, relevant to the next generation upgrades to the IceCube and Auger observatories.
Combined knowledge of all studied mass sensitive observables yields promising mass separation power, even when accounting for typical reconstruction uncertainties of the observables.
The combination of shower maximum and muon observables is of particular importance for event-by-event mass discrimination, while high-energy muons (> 500 GeV), measurable by IceCube, serve as an important mass sensitive observable on their own.
This motivates equipping the next generation of air-shower arrays with multiple detection techniques for the simultaneous measurement of these shower observables.