Depth of maximum of air-shower profiles at the Pierre Auger Observatory. I. Measurements at energies above 1017.8eV

Document Type

Article

Publication Date

12-31-2014

Abstract

© 2014 American Physical Society. We report a study of the distributions of the depth of maximum, Xmax, of extensive air-shower profiles with energies above 1017.8eV as observed with the fluorescence telescopes of the Pierre Auger Observatory. The analysis method for selecting a data sample with minimal sampling bias is described in detail as well as the experimental cross-checks and systematic uncertainties. Furthermore, we discuss the detector acceptance and the resolution of the Xmax measurement and provide parametrizations thereof as a function of energy. The energy dependence of the mean and standard deviation of the Xmax distributions are compared to air-shower simulations for different nuclear primaries and interpreted in terms of the mean and variance of the logarithmic mass distribution at the top of the atmosphere.

Publication Title

Physical Review D - Particles, Fields, Gravitation and Cosmology

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