Direct Measurement of the Muon Density in Air Showers with the Pierre Auger Observatory

S. MÜLLER; THE PIERRE AUGER COLLABORATION.; S. J. SCIUTTO

Simposio; International Symposium on Ultra High Energy Cosmic Rays UHECR 2018; 2018

As part of the upgrade of the Pierre Auger Observatory, the Auger Muons and Infill for the GroundArray (AMIGA) underground muon detector extension will allow for direct muon measurements for showersfalling into the SD-750 array. We optimized the AMIGA muon reconstruction procedure by introducing ageometrical correction for muons leaving a signal in multiple detector strips due to their inclined angle ofincidence and deriving a new unbiased parametrization of the muon lateral distribution function. Furthermore,we defined a zenith-independent estimator 35 of the muon density by parametrizing the attenuation of themuonic signal due to the atmosphere and soil layer above the buried detectors and quantified the relevantsystematic uncertainties for AMIGA. The analysis of one year of calibrated data recorded with the prototypearray of AMIGA confirms the results of previous studies indicating a disagreement between the muon contentin simulations and data.