Inferring hadronic interaction properties from the 2D distribution of muon content and depth of maximum of extensive air showers

Abstract

As ultra-high-energy cosmic rays collide with nuclei in the atmosphere, at center-of-mass energies exceeding by more than an order of magnitude those achievable at current human-made colliders, they initiate vast cascades of secondary particles known as Extensive Air Showers. These showers evolve through the re-interaction and propagation of secondary particles originating from hadronic interactions that cannot be calculated from first principles of Quantum Chromodynamics. Instead, these interactions are described by phenomenological hadronic interaction models that are poorly constrained by accelerator data. The uncertainty in the extrapolations of these models hampers the interpretation of the mass composition of the cosmic-ray flux, thereby hindering efforts to identify the sources of ultra-high-energy cosmic rays.