U. Giaccari

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We describe the measurement of the depth of maximum, X{max}, of the longitudinal development of air showers induced by cosmic rays. Almost 4000 events above 10;{18} eV observed by the fluorescence detector of the Pierre Auger Observatory in coincidence with at least one surface detector station are selected for the analysis. The average shower maximum was(More)
J. Abraham, P. Abreu, M. Aglietta, E. J. Ahn, D. Allard, I. Allekotte, J. Allen, J. Alvarez-Muñiz, M. Ambrosio, L. Anchordoqui, S. Andringa, T. Antičić, A. Anzalone, C. Aramo, E. Arganda, K. Arisaka, F. Arqueros, H. Asorey, P. Assis, J. Aublin, M. Ave, G. Avila, T. Bäcker, D. Badagnani, M. Balzer, K. B. Barber, A. F. Barbosa, S. L. C. Barroso, B. Baughman,(More)
Energy-dependent patterns in the arrival directions of cosmic rays are searched for using data of the Pierre Auger Observatory. We investigate local regions around the highest-energy cosmic rays with E ≥ 6×1019 eV by analyzing cosmic rays with energies above E ≥ 5×1018 eV arriving within an angular separation of approximately 15◦. We characterize the energy(More)
  • A Aab, P Abreu, +434 authors F Zuccarello
  • Physical review letters
  • 2016
Ultrahigh energy cosmic ray air showers probe particle physics at energies beyond the reach of accelerators. Here we introduce a new method to test hadronic interaction models without relying on the absolute energy calibration, and apply it to events with primary energy 6-16 EeV (E_{CM}=110-170  TeV), whose longitudinal development and lateral distribution(More)
We present the results of an analysis of the large angular scale distribution of the arrival directions of cosmic rays with energy above 4 EeV detected at the Pierre Auger Observatory including for the first time events with zenith angle between 60° and 80°. We perform two Rayleigh analyses, one in the right ascension and one in the azimuth angle(More)
We describe the method devised to reconstruct inclined cosmic-ray air showers with zenith angles greater than 60 detected with the surface array of the Pierre Auger Observatory. The measured signals at the ground level are fitted to muon density distributions predicted with atmospheric cascade models to obtain the relative shower size as an overall(More)
We measure the energy emitted by extensive air showers in the form of radio emission in the frequency range from 30 to 80 MHz. Exploiting the accurate energy scale of the Pierre Auger Observatory, we obtain a radiation energy of 15.8±0.7(stat)±6.7(syst)  MeV for cosmic rays with an energy of 1 EeV arriving perpendicularly to a geomagnetic field of 0.24 G,(More)
We report a measurement of the proton-air cross section for particle production at the center-of-mass energy per nucleon of 57 TeV. This is derived from the distribution of the depths of shower maxima observed with the Pierre Auger Observatory: systematic uncertainties are studied in detail. Analyzing the tail of the distribution of the shower maxima, a(More)
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