The energy spectrum of cosmic rays above 2.5×1018eV, derived from 20000 events recorded at the Pierre Auger Observatory, is described. The spectral index γ of the particle flux, JE-γ, at energies between 4×1018eV and 4×1019eV 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 greater than 6 standard deviations. The data are consistent with the prediction by Greisen and by Zatsepin and Kuz'min. © 2008 The American Physical Society.

Observation of the suppression of the flux of cosmic rays above 4×1019eV

Caruso R.;Insolia A.;
2008

Abstract

The energy spectrum of cosmic rays above 2.5×1018eV, derived from 20000 events recorded at the Pierre Auger Observatory, is described. The spectral index γ of the particle flux, JE-γ, at energies between 4×1018eV and 4×1019eV 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 greater than 6 standard deviations. The data are consistent with the prediction by Greisen and by Zatsepin and Kuz'min. © 2008 The American Physical Society.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/20.500.11769/487379
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