Latest Results from HiRes
Jul, 200810 pages
Part of Proceedings, 20th Rencontres de Blois on Challenges in Particle Astrophysics : Blois, France, May 18-23, 2008, 45-54
Contribution to:
e-Print:
- 0807.2814 [astro-ph]
View in:
Citations per year
Abstract: (arXiv)
HiRes has made the first statistically significant observation of the Griessen-Zatsepin-Kuzmin suppression, by fitting the ultra high energy cosmic ray spectrum observed in monocular mode by the two HiRes detectors to a broken power law model. We find the break to be at an energy of eV, with a significance of ;. The significance is determined by Poisson statistics where we expect 43.2 events above the break point, but observe only 13. We have also looked for correlations between HiRes stereo events and active galactic nuclei. We observe no statistically significant correlation in a number of different tests. We have performed a search for upward going showers, which would be indicative of neutrinos propagating through the Earth and interacting just below the surface. Observing no such events, we set a limit on the electron neutrino flux. This limit is significantly lower in this topology than limits on the other types of neutrinos due to the LPM effect greatly increasing the available target mass for neutrino interactions. Finally we look forward to improving these and other results in our work in the Telescope Array.Note:
- 10 pages, 8 figures, to appear in the Proceedings of the 20th Recontres de Blois, Blois, France, May 2008
- GZK effect
- neutrino: interaction
- neutrino: flux
- cosmic radiation: energy spectrum
- AGN
- correlation
References(16)
Figures(8)