Cosmic rays and hadronic interactions

The fields of cosmic rays and hadronic interactions are intimately related. High-energy cosmic rays can only be studied detecting the showers they generate in the atmosphere, and the interpretation of the data requires the precise modeling of hadronic interactions. Uncertainties in this modeling are in many cases an important limitation for cosmic ray studies. The cosmic ray spectrum extends to particles with energy E ∼ 10 20   eV , which, assuming that the primary particle is a proton, corresponds to a nucleon–nucleon c.m. energy s ≃ 430   TeV , 50 times higher than the current LHC energy. Cosmic ray studies require an extrapolation of the results obtained at accelerators, but also offer the possibility to perform studies on the properties of hadronic interactions that are impossible at accelerators.