“Observation of the Suppression of the Flux of Cosmic Rays above 4x1019 eV”

J. ABRAHAM (GARCIA, B. Y 400 AUTORES DE LA COL. INTERNACIONAL PIERRE AUGER)

PHYSICAL REVIEW LETTERS

American Physical Society

Lugar: Chicago; Año: 2008 p. 1101 - 1107

0031-9007

   The energy spectrum of cosmic rays above 2:5 1018 eV, derived from 20 000 events recorded at thePierre Auger Observatory, is described. The spectral index   of the particle flux, J / Eÿ  , at energiesbetween 4 1018 eV and 4 1019 eV is 2:69 0:02…stat† 0:06…syst†, steepening to 4:2 0:4…stat† 0:06…syst† at higher energies. The hypothesis of a single power law is rejected with a significance greaterthan 6 standard deviations. The data are consistent with the prediction by Greisen and by Zatsepin andKuz’min.