22-24 May 2013
Physics Department, University "La Sapienza", Roma, Italy
Europe/Rome timezone

Cosmic Ray Composition with the Pierre Auger Observatory

22 May 2013, 10:20
Aula Edoardo Amaldi (first floor) (Physics Department, University "La Sapienza", Roma, Italy)

Aula Edoardo Amaldi (first floor)

Physics Department, University "La Sapienza", Roma, Italy


Denise Boncioli (INFN Laboratori Nazionali del Gran Sasso)


The Pierre Auger Observatory in Argentina is the largest cosmic ray detector array ever built. Although the construction was completed in 2008, the Observatory has been taking data continuously since January 2004. Its main goal is to measure ultra high energy cosmic rays (UHECRs, energy above $10^{18}$ eV) with unprecedented statistics and precision. Measurements of the energy spectrum, chemical composition (including neutrinos and photons) and arrival directions of UHECRs can provide hints for understanding their origin, propagation and interactions. The Fluorescence Detector of the Pierre Auger Observatory measures the atmospheric depth, $X_{max}$, where the longitudinal profile of the high energy air showers reaches its maximum. This is sensitive to the nuclear mass composition of the cosmic rays and to the characteristics of the hadronic interactions at very high energy. Due to its hybrid design, the Pierre Auger Observatory also provides independent experimental observables obtained from the Surface Detector for the study of the nuclear mass composition. A selection of the Pierre Auger Observatory results on the study of the UHECRs will be presented, focusing on the composition results. In particular, the measurements and the different roles of the observables with respect to mass composition will be discussed.

Primary author

Denise Boncioli (INFN Laboratori Nazionali del Gran Sasso)


Presentation Materials

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