Related papers: Towards solving the mass-composition problem in ul…
There are multiple techniques to determine the chemical composition of the ultra-high-energy cosmic rays. While most of the methods are primarily sensitive to the average atomic mass, it is challenging to discriminate between the two…
The Pierre Auger Observatory has conducted measurements of the energy spectrum and mass composition of cosmic rays using different methods. Utilizing both surface and fluorescence detectors (SD and FD), the Observatory provides…
We demonstrate that the energy spectra of Ultra High Energy Cosmic Rays (UHECR) as observed by AGASA, Fly's Eye, HiRes and Yakutsk detectors, have the imprints of UHE proton interaction with the CMB radiation as the dip centered at $E\sim…
We present a new method for probing the hadronic interaction models at ultra-high energy and extracting details about mass composition. This is done using the time profiles of the signals recorded with the water-Cherenkov detectors of the…
We propose a new method for the estimation of ultra-high energy cosmic ray (UHECR) mass composition from a distribution of their arrival directions. The method employs a test statistic (TS) based on a characteristic deflection of UHECR…
The Pierre Auger Observatory has collected data for more than 15 years, accumulating the world's largest exposure to ultrahigh energy cosmic rays (UHECRs). The energy spectrum of the UHECRs has been measured up to $10^{20.2}$ eV, and their…
The signatures of UHE proton propagation through CMB are pair-production dip and GZK cutoff. The visible manifestations of these spectral features are ankle, beginning of GZK cutoff in the differential spectrum and E_{1/2} in integral…
We study a generic class of models for ultra-high energy cosmic ray (UHECR) phenomenology, in which the sources accelerate protons and nuclei with a power-law spectrum having the same index, but with different values for the maximum proton…
The greater part of this paper is concerned with a historical discussion of the development of the search for the origins of the highest-energy cosmic-rays together with a few remarks about future prospects. Additionally, in section 6, the…
The Pierre Auger Observatory advances the study of ultra-high-energy cosmic rays through a hybrid system of surface and fluorescence detectors. This paper presents recent results, including refined spectrum measurements, anisotropy…
The characteristics of an extensive air shower derive from both the mass of the primary ultra-high-energy cosmic ray that seeds its development and the properties of the hadronic interactions that feed it. With its hybrid detector design,…
The Pierre Auger Observatory has been designed to investigate the most energetic particles known, the ultra high energy cosmic rays. The observatory, covering an area of 3000 km^2, combines two different detection techniques to study the…
In this paper some recent results from the Pierre Auger Collaboration are presented. These are the measurement of the energy spectrum of cosmic rays over a wide range of energies ($10^{17.5}$ to above $10^{20}$ eV), studies of the…
Resonant photopion production with the cosmic microwave background predicts a suppression of extragalactic protons above the famous Greisen-Zatsepin-Kuzmin cutoff at about E_{GZK} ~ 5 x 10^10 GeV. Current cosmic ray data measured by the…
The status of the field of ultrahigh energy cosmic rays is summarized, from the point of view of the latest results of the High Resolution Fly's Eye (HiRes) Experiment. HiRes results are presented, and compared with those of the Akeno Giant…
Ground-based full-sky studies of the angular distribution of arrival directions of ultra-high-energy cosmic rays require combining data from different observatories, such as the Pierre Auger Observatory (Auger) and the Telescope Array (TA),…
The dip model assumes that the ultra-high energy cosmic rays (UHECRs) above 10$^{18}$ eV consist exclusively of protons and is consistent with the spectrum and composition measure by HiRes. Here we present the range of cosmogenic neutrino…
The origin and nature of ultra-high energy cosmic rays (UHECRs) are hot topics in the astroparticle physics community. The Fluorescence detector Array of Single-pixel Telescopes (FAST) is a design for a next-generation ground-based UHECR…
The Pierre Auger Collaboration has reported an excess in the number of muons of a few tens of percent over expectations computed using extrapolation of hadronic interaction models tuned to accommodate LHC data. Very recently, we proposed an…
The full-sky multipole coefficients of the ultra-high energy cosmic ray (UHECR) flux have been measured for the first time by the Pierre Auger and Telescope Array collaborations using a joint data set with E > 10 EeV. We calculate these…