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

F.SANCHEZ, THE PIERRE AUGER COLLABORATION (VER A. LUCERO EN LISTA AUTORES ARCHIVO ADJUNTO)

Wisconsin-Madison

Conferencia; 36th International Cosmic Ray Conference; 2019

University of Wisconsin-Madison, IUPAP

The muon densities at 450 m from the core for showers above 10^17.5 eV and zenith angle between 0◦ and 45◦ are presented. Results are based on 1 year of calibrated data collected by the engi- neering array of the Auger Muons and Infill for Ground Array (AMIGA) detector. Taking into account systematic uncertainties as well as attenuation effects, the observations suggest that the current 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 of 38% is required at both energies, while for QGSJetII-04 an increment of 50% and 53% is needed at respective energies. Data have been combined with previous results on muon densities at higher energies showing the match in the evolution of the composition derived with the measurements of depth of the maximum development of the showers in the atmosphere (Xmax). The current AMIGA observations show that the variation of the primary masses has no sudden changes in the energy range 10^17.5 to 10^18.0 eV.