Working Group Report on the Combined Analysis of Muon Density Measurements from Eight Air Shower Experiments

Understand

We present a meta-analysis of recent muon density measurements made by eight air shower experiments which cover shower energies ranging from PeV to tens of EeV regarding the muon puzzle in extensive air showers.

• Some experimental analyses reported deviations between recorded and simulated muon densities in extensive air showers, and others reported no discrepancies.
• Comparisons between experiments were made using a universal reference scale based on the relative difference to simulated proton and iron initiated air showers.
• We have applied a cross-calibration of energy scales between experiments based on the isotropic flux of cosmic rays as a reference.