Cosmic-Ray Air Showers at Sea Level

Clark, G. W.; Earl, J. A.; Kraushaar, W. L.; Linsley, J.; Rossi, Bruno; Scherb, F.; Scott, D.

doi:10.1103/physrev.122.637

Cited by 53 publications

(27 citation statements)

References 6 publications

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“…The pioneering development of the air shower techniques (and the first use of plastic scintillation detectors for the dual use of measuring arrival directions and particle densities) was started at the Agassiz Station of the Harvard College Observatory, a work carried out between 1954 and 1957 [7,8,9]. The existence of primary particles with energies greater than 10 18 eV was established by the observation of one shower with more than 10 9 particles.…”

Section: There's Something About Cosmic Ray Observations a Experimentioning

confidence: 99%

Astrophysical origins of ultrahigh energy cosmic rays

2004

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In the first part of this review we discuss the basic observational features at the end of the cosmic ray energy spectrum. We also present there the main characteristics of each of the experiments involved in the detection of these particles. We then briefly discuss the status of the chemical composition and the distribution of arrival directions of cosmic rays. After that, we examine the energy losses during propagation, introducing the Greisen-Zaptsepin-Kuzmin (GZK) cutoff, and discuss the level of confidence with which each experiment have detected particles beyond the GZK energy limit. In the second part of the review, we discuss astrophysical environments able to accelerate particles up to such high energies, including active galactic nuclei, large scale galactic wind termination shocks, relativistic jets and hot-spots of Fanaroff-Riley radiogalaxies, pulsars, magnetars, quasar remnants, starbursts, colliding galaxies, and gamma ray burst fireballs. In the third part of the review we provide a brief summary of scenarios which try to explain the super-GZK events with the help of new physics beyond the standard model. In the last section, we give an overview on neutrino telescopes and existing limits on the energy spectrum and discuss some of the prospects for a new (multi-particle) astronomy. Finally, we outline how extraterrestrial neutrino fluxes can be used to probe new physics beyond the electroweak scale. Solicited Review Article Prepared for Reports on Progress in Physics 1 PREFACEReviewing cosmic ray physics is a risky business. Theoretical models continue to appear at an amazing rate, both in the astrophysical and more exotic domains. We warn the reader: we do not (nor we could) intend to make an homogeneous coverage of all the ideas of our fellow colleagues. Reading differently focused reviews on the issue (quoted here along the way) is, in our view, the best approach to such a wide topic of research.2 Contents

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Section: There's Something About Cosmic Ray Observations a Experimentioning

confidence: 99%

Astrophysical origins of ultrahigh energy cosmic rays

2004

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“…Between 1954 and 1957 an array of 15 counters, each 0.9 m 2 , was operated at the Harvard Agassiz Station (Clark et al, 1961). Data from this array were used to derive the energy spectrum from 3ϫ10 15 to 10 18 eV.…”

Section: Historical Backgroundmentioning

confidence: 99%

Observations and implications of the ultrahigh-energy cosmic rays

2000

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The authors define ''ultrahigh-energy cosmic rays'' (UHECRs) as those cosmic rays with energies above 10 18 eV. It had been anticipated that there would be a cutoff in the energy spectrum of primary cosmic rays around 6ϫ10 19 eV induced by the interaction of the particles with the 2.7-K primordial photons. However, recent experimental data have established that particles exist with energies greatly exceeding this. It follows that the sources of such particles are probably nearby, on a cosmological scale. However, although the trajectories of such energetic particles through the galactic and intergalactic magnetic fields may be nearly rectilinear, no astronomical sources have as yet been identified. This is the enigma of the highest-energy cosmic rays. The paper reviews the history of research in this energy regime and critically assesses the observational results on the energy spectrum, arrival directions, and composition of the primary cosmic rays based on observations made by six experiments. The detection methods currently available are described. Special techniques have been developed as particles of 10 20 eV or higher occur at a rate of only about 1 per km 2 per century. Errors in measurement are given particular attention. The authors also review the theoretical predictions for a number of candidate sources of cosmic rays beyond the predicted cutoff. Finally, the four major projects planned to address the question of the origin of UHECRs are briefly described. CONTENTS

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“…The large spacing between the detectors presented difficulties for determining the number of particles in the shower. At the atmospheric depth of Volcano Ranch, 834 g cm -2 , the Molière radius is ~ 100 m and for two very large events of energies > 10 19 eV [1,2] it was argued that the size, N, could be inferred by integrating an average lateral distribution over all distances with the energy being deduced under the assumption that the showers were at the maximum of their development at the depth of observation. The conversion to primary energy was based on Greisen's method of the track-length integral.…”

Section: Detection Of Extensive Air Showers Using Surface Arrays and mentioning

confidence: 99%

“…1.1 Some background information about cosmic rays A detailed understanding of the properties and origin of cosmic rays with energies greater than 1 Joule (6.3 x 10 18 eV) remains lacking over 50 years after their discovery [1]. Following the first claim for an event above ~ 10 20 eV made by Linsley in 1963 using observations at Volcano Ranch [2], painstaking work by dedicated groups resulted in reports of detections of a small number of events above this energy.…”

Section: Introductionmentioning

confidence: 99%

High-energy cosmic rays and the Greisen–Zatsepin–Kuz'min effect

Watson

2014

Rep. Prog. Phys.

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Abstract:Although cosmic rays were discovered over 100 years ago their origin remains uncertain. They have an energy spectrum that extends from ~ 1 GeV to beyond 10 20 eV, where the rate is less than 1 particle per km 2 per century. Shortly after the discovery of the cosmic microwave background in 1965, it was pointed out that the spectrum of cosmic rays should steepen fairly abruptly above about 4 x 10 19 eV, provided the sources are distributed uniformly throughout the Universe. This prediction, by Greisen and by Zatsepin and Kuz'min, has become known as the GZK-effect and in this article I discuss the current position with regard to experimental data on the energy spectrum of the highest cosmic-ray energies that have been accumulated in a search that has lasted nearly 50 years. Although there is now little doubt that a suppression of the spectrum exists near the energy predicted, it is by no means certain that this is a manifestation of the GZK-effect as it might be that this energy is also close to the maximum to which sources can accelerate particles, with the highest-energy beam containing a large fraction of nuclei heavier than protons. The way forward is briefly mentioned.

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Cosmic-Ray Air Showers at Sea Level

Cited by 53 publications

References 6 publications

Astrophysical origins of ultrahigh energy cosmic rays

Astrophysical origins of ultrahigh energy cosmic rays

Observations and implications of the ultrahigh-energy cosmic rays

High-energy cosmic rays and the Greisen–Zatsepin–Kuz'min effect

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