Related papers: Improving photon-hadron discrimination based on co…
In a recently proposed model the cosmic rays spectrum at energies above 10^{18} eV can be fitted with a minimal number of unknown parameters assuming that the extragalactic cosmic rays are only protons with a power law source spectrum…
Atmospheric \v{C}erenkov Technique is an established methodology to study $TeV$ energy gamma rays. However the challenging problem has always been the poor signal to noise ratio due to the presence of abundant cosmic rays. Several ingenious…
Extensive air showers are complex objects, resulting of billions of particle reactions initiated by single cosmic ray at ultra-high-energy. Their characteristics are sensitive both to the mass of the primary cosmic ray and to the details of…
In extensive air showers induced by ultra-high-energy (UHE) cosmic rays, secondary photons are expected to be produced at energies far above those accessible by other means. It has been shown that the decay of such photons, as possible in…
Recent observations of cosmic ray protons in the energy range $10^2$--$10^5$~GeV have revealed that the spectrum cannot be described by a simple power law. A hardening of the spectrum around an energy of order few hundred~GeV, first…
We investigate the observed muon deficit in air shower simulations when compared to ultrahigh-energy cosmic ray (UHECR) data. Gleaned from the observed enhancement of strangeness production in ALICE data, the associated $\pi \leftrightarrow…
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…
Identification of primary cosmic rays on an event-by-event basis is a much-desired capability of cosmic-ray observatories. Several cosmic-ray air-shower experiments use so-called photon tags for gamma hadron primary particle discrimination.…
Measurements of proton and nuclear collisions at the Large Hadron Collider at nucleon-nucleon c.m. energies up to $\sqrt{s_{NN}}=$ 13 TeV, have improved our understanding of hadronic interactions at the highest energies reached in…
In the present work we carry out a study of the high energy cosmic rays mass identification capabilities of a hybrid detector employing both fluorescence telescopes and particle detectors at ground using simulated data. It involves the…
Simultaneous measurements of air showers with the fluorescence and surface detectors of the Pierre Auger Observatory allow a sensitive search for EeV photon point sources. Several Galactic and extragalactic candidate objects are grouped in…
Ground based observations appear to indicate that Ultra High Energy Cosmic Rays (UHECR) of the highest energies (>10^{18.7} eV) consist of heavy particles -- shower depth and muon production data both pointing towards this conclusion. On…
Diffuse photons of energy above 0.1 PeV, produced through the interactions between cosmic rays and either interstellar matter or background radiation fields, are powerful tracers of the distribution of cosmic rays in the Galaxy.…
We present an upper limit on the flux of ultra-high-energy down-going neutrinos for $E > 10^{18}\ \mbox{eV}$ derived with the nine years of data collected by the Telescope Array surface detector (05-11-2008 -- 05-10-2017). The method is…
We present a theoretical evaluation of radiation dose constraints for extreme ultraviolet (EUV) and soft X-ray microscopy. Our work particularly addresses the long-standing concern regarding strong absorption of EUV radiation in biological…
Interpretation of the energy spectrum and arrival distribution of cosmic rays is complicated by lack of knowledge of the nature of the primaries. We review claims for the mass composition above 1017 eV where it can be determined only…
We investigate the detection of exotic massive strongly interacting hadrons (uhecrons) in ultra high energy cosmic ray telescopes. The conclusion is that experiments such as the Pierre Auger Observatory have the potential to detect these…
With the prospect of measuring the fraction of arriving secondary photons, produced through photo-pion energy loss interactions of ultra high energy cosmic ray (UHECR) protons with the microwave background during propagation, we investigate…
Candidate astrophysical acceleration sites capable of producing the highest energy cosmic rays (E > 10^{19.5} eV) appear to be at far greater distances than is compatible with their being known particles. The properties of a new particle…
Measurements of cosmic ray particles at energies above E = 5 x 10^{14} eV are performed by large area ground based air shower experiments. Only they provide the collection power required for obtaining sufficient statistics at the low flux…