Cosmic rays are relativistic particles that come to the Earth from outer space. Despite a great
effort made in both experimental and theoretical research, their origin is still unknown. One …

Nature is providing particles with energies exceeding 100 EeV. Their existence imposes
immediate questions: Are they ordinary particles, accelerated in extreme astrophysical …

We present a general method for estimating the number of particles impinging on a
segmented counter or, in general, on a counter with sub-units. We account for unresolved …

In this paper, ultra-high-energy cosmic rays (UHECRs) are studied with giant ground-based
detector systems recording extensive air showers, induced by cosmic ray particles in the …

We present a measurement of the density of GeV muons in near-vertical air showers using
three years of data recorded by the IceTop array at the South Pole. Depending on the …

After more than 15 years of successful data taking, the Pierre Auger Observatory started a
major upgrade, called AugerPrime, whose main aim is the collection of new information …

Cosmic rays with energies above 1 PeV are studied using large (1 km2 to 1000 km2),
sparse arrays of detectors on the ground that observe the air showers that are produced in …

(1) Pions produced in the development of extended atmospheric cosmic ray air showers
subsequently decay to muons. The measured yield of those muons is generally …

In this letter, the Grey-Disk and the Core-Corona models are combined in a scenario that
aims to explain different unexpected features observed in the interactions of the highest …

Abstract The Pierre Auger Observatory is the largest extensive air shower detector. Based
on a hybrid system, this experiment measures the longitudinal shower development and the …