Related papers: Particle Physics at Ultrahigh Energies
Indications of a discrepancy between simulations and data on the number of muons in cosmic ray showers exist over a large span of energies. We focus on the excess of multi-muon bundles observed by the DELPHI detector at LEP and on the…
The top quark, being the heaviest particle of the Standard Model, is a prime candidate of where physics beyond the SM might currently hide before our eyes. There are many natural extensions of the SM that rely on top compositeness, and the…
This paper briefly summarizes the status of the cosmic ray observations by EAS (Extended Air Shower) experiments with energy below 10**16eV and the related studies of the hadronic interaction models. Based on the observed sharp knee…
High-energy cosmic rays are observed indirectly by detecting the extensive air showers initiated in Earth's atmosphere. The interpretation of these observations relies on accurate models of air shower physics, which is a challenge and an…
The first LHC results at 7-8 TeV, with the discovery of a candidate Higgs boson and the non observation of new particles or exotic phenomena, have made a big step towards completing the experimental confirmation of the Standard Model (SM)…
Accelerator physics beyond the LHC is expected to provide precision in the study of new physics processes which the LHC may have already unveiled and to extend the high energy frontier beyond its reach, in the multi-TeV domain. In this…
The hadron production in the simulation of extensive air showers is a long standing problem and the origin of large uncertainties in the reconstruction of the mass of the high energy primary cosmic rays. Hadronic interaction models re-tuned…
The identification of very high energy photons is of great importance for the understanding of the origin of extreme energy cosmic rays (EECR). Several can be the sources of high energy photons at Earth. A guaranteed component is the flux…
I present a concise review of where we stand in particle physics today. First, I will discuss QCD, then the electroweak sector and finally the motivations and the avenues for new physics beyond the Standard Model.
Decays of superheavy X particles with mass M_X ~ 10^12 - 10^16 GeV have been proposed as origin of the observed ultra high energy cosmic rays (UHECR). We describe in detail the physics involved in the different steps of the decay of such a…
The interaction of ultra-high energy cosmic rays with the atmosphere nuclei has long been seen as a unique opportunity to study hadronic interactions above energies attainable by accelerators. However, so far the multiparticle production…
We argue that the increase of the ratio baryon/meson due to the presence of strong colour fields and percolation in ultra-high energy hadronic collisions, helps to explain some of the global features of ultra-high energy cosmic ray cascades…
The observation of twenty cosmic-ray air-showers at and above 10^{20} eV poses fascinating problems for particle astrophysics: how the primary particles are accelerated to these energies, how the primaries get here through the 2.7K…
We demonstrate that the shower-to-shower fluctuations of the muon content of extensive air showers correlate with the fluctuations of a variable of the first interaction of Ultra High Energy Cosmic Rays, which is computed from the fraction…
Experimental prospects for studying high-energy photon-photon and photon-proton interactions at the LHC are discussed. Assuming a typical LHC multipurpose detector, various signals and their irreducible backgrounds are presented after…
Research in cosmic rays is now nearly a century old, but most of the fundamental questions in this field remain unanswered, on the other hand the perspectives of future studies in the next decade are very bright. New detectors will provide…
High-energy cosmic rays are observed indirectly by detecting the extensive air showers initiated in Earth's atmosphere. The interpretation of experimental data relies on accurate modeling of the air shower development. Simulations based on…
The current status of the ultrahigh energy cosmic ray (UHE CR) enigma and several proposed solutions involving particle physics beyond the standard model are discussed. Emphasis is given to top--down models, and as a main example,…
Significant progress has been made over the past decades towards unveiling the sources of the most energetic particles in nature, the ultra-high-energy cosmic rays (UHECRs). Despite these advancements, the exact astrophysical sites capable…
The Pierre Auger Observatory has driven the field of ultra-high-energy cosmic ray (UHECR) physics, producing several groundbreaking observations over the last 20 years. One of the most striking findings has been the complex evolution of…