Related papers: Experimental/Observational Summary - Very High Ene…
One of the most striking astrophysical phenomena today is the existence of cosmic ray particles with energies in excess of 10^20 eV. While their presence has been confirmed by a number of experiments, it is not clear where and how these…
Ultra high energy cosmic rays (UHECRs) are expected to be accelerated in astrophysical sources and to travel through extragalactic space before hitting the Earth atmosphere. They interact both with the environment in the source and with the…
We present a brief introduction to the physics of Ultra High Energy Cosmic Rays (UHECRs), concentrating on the experimental results obtained so far and on what, from these results, can be inferred about the sources of UHECRs.
Ultrahigh-energy cosmic rays (UHECRs) arrive at Earth from the most energetic astrophysical accelerators in the universe. They collide with atoms in the upper atmosphere with energies about ten times higher than any man-made accelerator,…
Cosmic rays are relativistic particles that come to the Earth from outer space. Despite a great effort made in both experimental and theoretical research, their origin is still unknown. One of the main keys to understand their nature is the…
We will discuss the main relevant aspects of the physics of ultra high energy cosmic rays. After a short recap of the experimental evidences, we will review theoretical models aiming at describing the sources of these extremely energetic…
Here we discuss the latest developments in the debate, where the ultrahigh energy cosmic ray particles come from. In this brief review, we emphasize the predictions that necessarily follow from the various concepts proposed. We discuss both…
We study the dependence of extensive air shower development on the first hadronic interactions at ultra-high energies occurring in the startup phase of the air shower cascade. The interpretation of standard air shower observables depends on…
We present an introductory lecture on general features of cosmic rays, for non-experts, and some recent developments concerning cascade equations for air shower developments.
We discuss the most recent developments in our understanding of the acceleration and propagation of cosmic rays up to the highest energies. In particular we specialize our discussion to three issues: 1) developments in the theory of…
The properties of cosmic rays with energies above 1PeV have to be deduced from the spacetime structure and particle content of the air showers which they initiate. In this review, a summary of the phenomenology of these giant air showers is…
The shape of the longitudinal development of the showers generated in the atmosphere by very high energy cosmic ray particles encodes information about the mass composition of the flux, and about the properties of hadronic interactions that…
The understanding of the nature of ultra-high-energy cosmic rays is one of the most intriguing open questions for current and future observatories. These particles are expected to be accelerated in extragalactic sources. Because of their…
Extensive air showers still are our only access to the highest-energy particles in the universe, namely cosmic-ray nuclei with energies up to several 100 EeV. Studying open questions in cosmic-ray physics, like their yet unknown origin…
We discuss the basic difficulties in understanding the origin of the highest energy particles in the Universe - the ultrahigh energy cosmic rays (UHECR). It is difficult to imagine the sources they are accelerated in. Because of the strong…
We study basic characteristics of distributions of the depths of shower maximum in air showers caused by cosmic rays with the highest energies. The consistency between their average values and widths, and their energy dependences are…
Cosmic-rays with energies exceeding 10^{19} eV are referred to as Ultra High Energy Cosmic Rays (UHECRs). The sources of these particles and their acceleration mechanism are unknown, and for many years have been the issue of much debate.…
A new method of investigating ultra-high energy cosmic ray sources is suggested. The method is based on analysis of gamma-ray emission that is generated in extragalactic space when ultra-high energy cosmic particles interact with cosmic…
Astroparticles offer a new path for research in the field of particle physics, allowing investigations at energies above those accesible with accelerators. Ultra-high energy cosmic rays can be studied via the observation of the showers they…
We review some of the recent progress in our knowledge about high-energy cosmic rays, with an emphasis on the interpretation of the different observational results. We discuss the effects that are relevant to shape the cosmic ray spectrum…