Highest energy cosmic-rays and results from the HiRes experiment

Sokolsky, P.; Thomson, G. B.

doi:10.1088/0954-3899/34/11/r01

Cited by 41 publications

(47 citation statements)

References 69 publications

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“…In what follows, we compare our predictions with HiRes [18] and Auger [9] spectra. Both experimental spectra have in common a high energy suppression of the flux but their shape are slightly different (harder in the case Auger) as well as the energy of the claimed suppressions, although both spectra are compatible within the claimed systematics.…”

Section: Spectrum Predictions For Various Source Composition Hypothesesmentioning

confidence: 99%

Implications of the cosmic ray spectrum for the mass composition at the highest energies

Allard

Busca

Decerprit

et al. 2008

J. Cosmol. Astropart. Phys.

137

179

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Abstract. The significant attenuation of the cosmic-ray flux above ∼ 5 10 19 eV suggests that the observed high-energy spectrum is shaped by the so-called GZK effect. This interaction of ultra-high-energy cosmic rays (UHECRs) with the ambient radiation fields also affects their composition. We review the effect of photo-dissociation interactions on different nuclear species and analyze the phenomenology of secondary proton production as a function of energy. We show that, by itself, the UHECR spectrum does not constrain the cosmic-ray composition at their extragalactic sources. While the propagated composition (i.e., as observed at Earth) cannot contain significant amounts of intermediate mass nuclei (say between He and Si), whatever the source composition, and while it is vastly proton-dominated when protons are able to reach energies above 10 20 eV at the source, we show that the propagated composition can be dominated by Fe and sub-Fe nuclei at the highest energies, either if the sources are very strongly enriched in Fe nuclei (a rather improbable situation), or if the accelerated protons have a maximum energy of a few 10 19 eV at the sources. We also show that in the latter cases, the expected flux above 3 10 20 eV is very much reduced compared to the case when protons dominate in this energy range, both at the sources and at Earth.

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Section: Spectrum Predictions For Various Source Composition Hypothesesmentioning

confidence: 99%

Implications of the cosmic ray spectrum for the mass composition at the highest energies

Allard

Busca

Decerprit

et al. 2008

J. Cosmol. Astropart. Phys.

137

179

View full text Add to dashboard Cite

show abstract

“…High resolution measurements of the UHECR spectrum, composition, and arrival direction have been allowed by recent experiments like AGASA [2], HiRes [3], the Pierre Auger Observatory [4], and Telescope Array [5]. Among the most interesting recent results, one can cite (see [6]) the evidence for a suppression of the UHECR flux above 3-5×10 19 eV observed by HiRes [7,8] and Auger [9] with a large significance. Furthermore, the recent analyses at the Pierre Auger Observatory seem to indicate an evolution of the composition toward heavier elements above the ankle [10] as well as hints for an anisotropic distribution of the arrival directions of the highest energy events [11] and in particular a possible diffuse excess in the direction of the Centaurus constellation [12].…”

Section: Introductionmentioning

confidence: 99%

Extragalactic propagation of ultrahigh energy cosmic-rays

Allard

2012

Astroparticle Physics

127

136

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In this paper we review the extragalactic propagation of ultrahigh energy cosmic-rays (UHECR). We present the different energy loss processes of protons and nuclei, and their expected influence on energy evolution of the UHECR spectrum and composition. We discuss the possible implications of the recent composition analyses provided by the Pierre Auger Observatory. The influence of extragalactic magnetic fields and possible departures from the rectilinear case are also mentioned as well as the production of secondary cosmogenic neutrinos and photons and the constraints their observation would imply for the UHECRs origin. Finally, we conclude by briefly discussing the relevance of a multi messenger approach for solving the mystery of UHECRs.

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“…Over the last forty years a variety of experiments have studied the cosmic ray spectrum at extreme energies 1 . It has been known for some time that this spectrum exhibits significant structure which must reflect the cosmic ray origins and propagation.…”

Section: Introductionmentioning

confidence: 99%

Final Results from the High solution Flyʼs Eye (HiRes) Experiment

Sokolsky

2011

Nuclear Physics B - Proceedings Supplements

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Final results from the High Resolution Fly's Eye (HiRes) on the observation of the Greisen-Zatsepin-Kuzmin cutoff in the cosmic ray spectrum are presented. We observe a cutoff consistent with the GZK predictions with a five sigma significance. The nature of the cosmic ray composition near the GZK cutoff is also discussed as well as possible correlations of the highest energy cosmic rays with AGNs and LSS in the Northern sky.

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Highest energy cosmic-rays and results from the HiRes experiment

Cited by 41 publications

References 69 publications

Implications of the cosmic ray spectrum for the mass composition at the highest energies

Implications of the cosmic ray spectrum for the mass composition at the highest energies

Extragalactic propagation of ultrahigh energy cosmic-rays

Final Results from the High solution Flyʼs Eye (HiRes) Experiment

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