The muon component of extensive air showers above 10^17.5 eV measured with the Pierre Auger Observatory

F. SANCHEZ, FOR THE AUGER COLLABORATION

Madisno

Conferencia; 36th International Cosmic Ray Conference (ICRC 2019); 2019

University of Madison

The muon densities at 450 m from the core for showers above 10 17.5 eV and zenith angle between0deg and 45deg are presented. Results are based on 1 year of calibrated data collected by the engineering array of the Auger Muons and Infill for Ground Array (AMIGA) detector. Taking intoaccount systematic uncertainties as well as attenuation effects, the observations suggest that thecurrent hadronic interaction models fail in reproducing the measured number of muons with en-ergies >1 GeV. Simulations at 10 17.5 eV and 10 18.0 eV show that for EPOS-LHC an increase of38% is required at both energies, while for QGSJetII-04 an increment of 50% and 53% is neededat respective energies. Data have been combined with previous results on muon densities at higherenergies showing the match in the evolution of the composition derived with the measurementsof depth of the maximum development of the showers in the atmosphere (Xmax). The currentAMIGA observations show that the variation of the primary masses has no sudden changes in theenergy range 10 17.5 to 10 18.0 eV.