Related papers: A Likelihood Method for Measuring the Ultrahigh En…
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 Pierre Auger Observatory infers the chemical composition of ultra-high-energy cosmic rays through two independent detection techniques. The Fluorescence Detector (FD) measures the longitudinal profile of high energy air showers and can…
Ultra high energy cosmic rays provide the highest known energy source in the universe to measure proton cross sections. Though conditions for collecting such data are less controlled than an accelerator environment, current generation…
We explore the feasibility of estimating primary cosmic ray composition at ultra high energies from the sum of muon, electron and photon densities and the depth of maximum of extensive air showers detected by the Auger Observatory. From the…
We present measurements of the atmospheric depth of the shower maximum $X_\mathrm{max}$, inferred for the first time on an event-by-event level using the Surface Detector of the Pierre Auger Observatory. Using deep learning, we were able to…
We present a new methodology to discriminate between light and heavy ultra-high energy cosmic-ray primaries on an event-by-event basis using information from the radio detection of extensive air showers at MHz frequencies. Similarly to…
The chemical composition of ultra high energy cosmic rays is still uncertain. The latest results obtained by the Pierre Auger Observatory and the HiRes Collaboration, concerning the measurement of the mean value and the fluctuations of the…
Measuring the angles of muons and electrons in air showers is proposed as a method for studying the primary cosmic-ray mass composition near the knee of the cosmic-ray energy spectrum at a few $10^{15}$ eV. Conventional tracking detectors…
We apply statistical inference on the Pierre Auger Open Data to discern for the first time the full mass composition of cosmic rays at different energies. Working with longitudinal electromagnetic profiles of cosmic ray showers, in…
We study the possibility of primary mass estimation for Ultra High Energy Cosmic Rays (UHECR's) using the $X_{max}^{\mu}$ (the height where the number of muons produced on the core of Extensive Air Showers (EAS) is maximum) and the number…
The fluorescence technique has been successfully used to detect ultrahigh energy cosmic rays by indirect measurements. The underlying idea is that the number of charged particles in the atmospheric shower, i.e, its longitudinal profile, can…
The Pierre Auger Observatory has been collecting data in a stable manner since January 2004. We present here a study of the cosmic ray composition using events recorded in hybrid mode during the first years of data taking. These are air…
At higher energies the uncertainty in the estimated cosmic ray mass composition, extracted from the observed distributions of the depth of shower maximum $X_\text{max}$, is dominated by uncertainties in the hadronic interaction models.…
The mass composition of ultra-high-energy cosmic rays is an open problem in astroparticle physics. It is usually inferred from the depth of the shower maximum (Xmax) of cosmic-ray showers, which is only ambiguously determined by modern…
The determination of the mass composition of the highest energy cosmic rays is one of the greatest challenges in cosmic ray experiments. The highest energy cosmic rays are only detected indirectly because of their very low flux. Using the…
The fluorescence technique has been successfully used to detect ultrahigh energy cosmic rays by indirect measurements. The underlying idea is that the number of charged particles in the atmospheric shower, i.e, its longitudinal profile, can…
The Fluorescence Detector of the Pierre Auger Observatory measures the atmospheric depth, $X_{max}$, where the longitudinal profile of the high energy air showers reaches its maximum. This is sensitive to the nuclear mass composition of the…
Measurements are reported on the fluorescence of air as a function of depth in electromagnetic showers initiated by bunches of 28.5 GeV electrons. The light yield is compared with the expected and observed depth profiles of ionization in…
We present measurements of the depth of shower maximum, Xmax, for cosmic-ray-induced extensive air showers recorded by the fluorescence detector of the Pierre Auger Observatory over 17 years. The data set covers primary energies from…
The Telescope Array observatory utilizes fluorescence detectors and surface detectors to observe air showers produced by ultra high energy cosmic rays in the Earth's atmosphere. Cosmic ray events observed in this way are termed hybrid data.…