The JEM-EUSO mission

Abstract

The JEM-EUSO mission aims at studying the origin of the extreme energy cosmic rays (EECRs) beyond the GZK suppression and exploring fundamental physics at these extreme energies, through the observations of the arrival directions and energies of these particles. It is designed to open a new particle astronomy channel. This super-wide-field (60degrees) telescope, with a diameter of about 2.5m, looks down from space observing the nighttime earth’s atmosphere to detect near UV photons at 330–400nm (both fluorescent and Cherenkov photons) emitted from the giant air showers produced by EECRs. The high statistics arrival direction map, expected to have at least more than five hundred events at the highest energies, will allow the identification of individual sources of EECRs, and their association with known near astronomical objects, uncovering therefore the origin of the EECRs. This will open the door to ultra-high energy astronomy, leading to an understanding of the acceleration mechanisms and, perhaps, producing discoveries in astrophysics and/or fundamental physics. The comparison of the energy spectra among the spatially resolved individual sources will help to clarify the acceleration/emission mechanisms, and will eventually confirm the Greisen–Zatsepin–Kuz’min process validating Lorentz invariance up to γ∼1011. Neutral components (neutrinos and gamma rays) can also be detected as well, if their fluxes are high enough.