Highest energy particle physics with the Pierre Auger Observatory
  Astroparticles offer a new path for research in the field of particle physics, allowing investigations at energies above those accesible with accelerators. Ultra-high energy cosmic rays can be studied via the observation of the showers they generate in the atmosphere. The Pierre Auger Observatory is a hybrid detector for ultra-high energy cosmic rays, combining two complementary measurement techniques used by previous experiments, to get the best possible measurements of these air showers. Shower observations enable one to not only estimate the energy, direction and most probable mass of the primary cosmic particles but also to obtain some information about the properties of their hadronic interactions. Results that are most relevant in the context of determining hadronic interaction characteristics at ultra-high energies will be presented. 
Analisa Mariazzi (for the Pierre Auger Collaboration)
astro-ph.HE