Related papers: Particle physics in cosmic rays
The Pierre Auger Observatory is the largest astroparticle experiment in operation. Complementary to the measurements of the charged ultra-high energy (UHE) cosmic rays, it provides a very good sensitivity to the detection of UHE photons and…
The Pierre Auger Observatory stands as the largest detector for ultra-high-energy (UHE) cosmic rays. The Observatory is also sensitive to UHE photons and neutrinos that can be produced along with UHE cosmic rays or in top-down processes,…
We present an analysis of the correlation between the depth of the maximum of air-shower profiles and the signal in water-Cherenkov stations in events registered simultaneously by the fluorescence and surface detectors of the Pierre Auger…
In order to get the primary energy of cosmic rays from their extensive air showers using the fluorescence detection technique, the invisible energy should be added to the measured calorimetric energy. The invisible energy is the energy…
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…
To interpret the mean depth of cosmic ray air shower maximum and its dispersion, we parametrize those two observables as functions of the first two moments of the $\ln A$ distribution. We examine the goodness of this simple method through…
The Pierre Auger Observatory is a hybrid detector for ultrahigh energy cosmic rays (UHECR) with energies above 10$^{18.5}$ eV. Currently the first part of the Observatory nears completion in the southern hemisphere in Argentina. One…
Data taken at the Pierre Auger Observatory are used to search for air showers initiated by ultra-high energy (UHE) photons. Results of searches are reported from hybrid observations where events are measured with both fluorescence and array…
The Pierre Auger Observatory is the world's largest cosmic ray observatory. Our current exposure reaches nearly 40,000 km$^2$ str and provides us with an unprecedented quality data set. The performance and stability of the detectors and…
The sources of the observed ultra-high energy cosmic rays must also generate ultra-high energy neutrinos. Deep inelastic scattering of these neutrinos with nucleons on Earth probe center-of-mass energies $\sqrt{s} \sim 100$ TeV, well beyond…
The observation of photons with energies above 10^18 eV would open a new window in cosmic-ray research, with possible impact on astrophysics, particle physics, cosmology and fundamental physics. Current and planned air shower experiments,…
This paper summarizes the status and the recent measurements from the Pierre Auger Observatory. The energy spectrum is described and its features discussed. We report searches for anisotropy of cosmic ray arrival directions on large scales…
The combined data of Fluorescence and Surface Detectors of the Pierre Auger Observatory has recently provided the strongest constraints on the validity of predictions from current models of hadronic interactions. The unmodified predictions…
The Pierre Auger Observatory, being the largest air-shower experiment in the world, offers an unprecedented exposure to neutral particles at the highest energies. Since the start of data taking more than 18 years ago, various searches for…
We report on studies of the composition of ultra high energy cosmic rays with the Pierre Auger Observatory. The detection of longitudinal air shower profiles with the fluorescence detector is described and the measurement of the average…
In its Phase I, the Pierre Auger Observatory has led to several observations, driving the field of ultra-high-energy cosmic ray (UHECR) research over the last 20 years. Major achievements obtained so far include the unprecedented precise…
The origin and nature of ultra high energy cosmic rays remains being a mystery. However, great progress has been made in recent years due to the observations performed by the Pierre Auger Observatory and Telescope Array. In particular, it…
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…
We present the first measurement of the fluctuations in the number of muons in extensive air showers produced by ultrahigh energy cosmic rays. We find that the measured fluctuations are in good agreement with predictions from air shower…
The Pierre Auger Observatory is a hybrid detector for ultra-high energy cosmic rays. It combines a surface array to measure secondary particles at ground level together with a fluorescence detector to measure the development of air showers…