Inclined showers at the Pierre Auger Observatory: reconstruction, energy calibration and implications for the muon content

THE PIERRE AUGER COLLABORATION (AUTOR 434 DE 474); M. TUEROS (COAUTOR)

Beijing

Conferencia; 32ns International Cosmic Ray Conference 2011; 2011

Institute of High Energy Physics, Chinese Academy of Sciences

The properties of extensive air showers (EAS) induced by cosmic rays with zenith angles up to 80◦ can be measured accurately in the surface detector (SD) of the Pierre Auger Observatory. Using a model of the density pattern of muons, extracted from simulations, the shower size, N19, related to the total number of muons in EAS, is estimated from the signals measured in the SD stations. The accuracy of the reconstruction of N19 is tested using a large sample of simulated events. The shower size is calibrated using the shower energy measured with the fluorescence detector (FD) in a sub-sample of high-quality hybrid events (i.e. events detected simultaneously by SD and FD). This allows the number of muons versus energy to be measured. We compare the number of muons versus energy as obtained through simulations with that measured in data. We find that none of the current shower models, neither for proton nor for iron primaries, are able to predict as many muons as are observed.