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Is the End in Sight for Ultrahigh Energy Cosmic Rays (UHECR)?

Is the End in Sight for Ultrahigh Energy Cosmic Rays (UHECR)?. S. Sakir: [ http://physicsweb.org/article/world/15/9/3 ] J. Bahcall + E. Waxman: [ hep-ph/0206217 v3 ]. Mark Pearce September 3 rd 2002. Cosmic Ray Energy Spectrum. Balloons and Satellites. Cosmic ray astronomy?

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Is the End in Sight for Ultrahigh Energy Cosmic Rays (UHECR)?

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  1. Is the End in Sight for Ultrahigh Energy Cosmic Rays (UHECR)? S. Sakir: [http://physicsweb.org/article/world/15/9/3] J. Bahcall + E. Waxman: [hep-ph/0206217 v3] Mark Pearce September 3rd 2002 Mark Pearce - KTH Stockholm -

  2. Cosmic Ray Energy Spectrum Balloons and Satellites • Cosmic ray astronomy? • Galactic magnetic field = mG • CR with energies > ~1018 GeV should point back to source LHC LEP UHECR Mark Pearce - KTH Stockholm -

  3. Types of Experiment • Air Flourescence • Fly’s Eye, HiRes, Utah • Ground Arrays • AGASA, Japan • Yakutsk, Siberia Mark Pearce - KTH Stockholm -

  4. Results From AGASA One idea: slow decay of relic supermassive [O(1012) GeV] dark matter particles, ’cryptons’. AGASA Spectrum expected from uniform distribution of cosmologically distant sources Mark Pearce - KTH Stockholm -

  5. p Mark Pearce - KTH Stockholm -

  6. The GZK (Greisen Zatsepin Kuzmin) Limit • When this process is energetically allowed (~ 5 x 1019 eV), space becomes opaque to cosmic rays • CR with energies above the GZK limit must be ’close’, < 100 Mpc • ie: within the well known local galactic cluster... • No known acceleration sites for such high energies... Mark Pearce - KTH Stockholm -

  7. Ignoring AGASA... [AGASA (exposure >1020 eV  1.3 103 km2 yr sr)] Yakutsk (0.9) Fly’s Eye (0.9) No GZK cut-off *HiRes (2.2) Galactic cosmic rays Cosmologically distance gamma-ray burst model (hep-ph/0206217) * Unpublished Mark Pearce - KTH Stockholm -  No exotic processes needed! 1020 eV

  8. The Pierre Auger Observatory • Auger will combine combine air fluorescence with ground arrays cross-calibration • Mendoza site: 1600 x 10k litre Cerenkov detectors / 30 air flourescence / 3000 km2 / 1.5km pitch • First results recorded from an engineering set-up last year. Full set-up by end 2004. Mark Pearce - KTH Stockholm - • Auger should settle the issue once and for all...

  9. Journal Club Scoreboard Mark Pearce - KTH Stockholm - NB: Present 2 / attend 6 / 2 pages your own / 4 x 1 page on others

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