The importance of muon information on primary mass discrimination of ultra-high energy cosmic rays

D. SUPANITSKY; A. TIBA; G. MEDINA-TANCO; A. ETCHEGOYEN; I. ALLEKOTTE; M. GÓMEZ BERISSO; V. DE SOUZA; C. MEDINA; A. J. ORTIZ; R. SHELLARD

Pune, India

Conferencia; 29th International Cosmic Ray Conference; 2005

Several methods can be used to perform statistical inference of primary composition of cosmic rays measured with water Cherenkov detectors as those in use at the Pierre Auger Southern Observatory. In the present work we assess the impact of additional information about the number of muons in the air shower, on the problem of statistical primary mass discrimination. Several tools are studied, including neural networks, principal component analysis and traditional methods in current use in the field. For our case study we use hypothetical plastic scintillators as muon counters, buried at the side and outside the shade of the water Cherenkov tanks. The study is extended to protons, Si and Fe nuclei impinging on an array with two different spacings, 750 and 1500 m and, therefore, suitable to the 1-10 EeV energy range. A prototype of such a detector is under construction.