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Observation Of The Suppression Of The Flux Of Cosmic Rays Above 4 X 1019 Ev, J. Abraham, Gregory Snow, The Pierre Auger Collaboration
Observation Of The Suppression Of The Flux Of Cosmic Rays Above 4 X 1019 Ev, J. Abraham, Gregory Snow, The Pierre Auger Collaboration
Gregory Snow Publications
The energy spectrum of cosmic rays above 2.5 x 1018 eV, derived from 20 000 events recorded at the Pierre Auger Observatory, is described. The spectral index γ of the particle flux, J/ E- γ , at energies between 4 x 1018 eV and 4 x 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 greater than 6 standard deviations. The data are consistent with the prediction by Greisen and by Zatsepin and Kuz’min.
Upper Limit On The Diffuse Flux Of Ultrahigh Energy Tau Neutrinos From The Pierre Auger Observatory, J. Abraham, Gregory Snow, Pierre Auger Collaboration
Upper Limit On The Diffuse Flux Of Ultrahigh Energy Tau Neutrinos From The Pierre Auger Observatory, J. Abraham, Gregory Snow, Pierre Auger Collaboration
Gregory Snow Publications
The surface detector array of the Pierre Auger Observatory is sensitive to Earth-skimming tau neutrinos that interact in Earth’s crust. Tau leptons from ντ charged-current interactions can emerge and decay in the atmosphere to produce a nearly horizontal shower with a significant electromagnetic component. The data collected between 1 January 2004 and 31 August 2007 are used to place an upper limit on the diffuse flux of ντ at EeV energies. Assuming an Eν-2 differential energy spectrum the limit set at 90% C.L. is Eν-2dNντ/dEν<1.3 x 10-7 GeV cm …