Search results for "Hadronic interaction"
showing 4 items of 4 documents
Testing Hadronic Interactions at Ultrahigh Energies with Air Showers Measured by the Pierre Auger Observatory
2016
Ultrahigh energy cosmic ray air showers probe particle physics at energies beyond the reach of accelerators. Here we introduce a new method to test hadronic interaction models without relying on the absolute energy calibration, and apply it to events with primary energy 6-16 EeV (ECM=110-170 TeV), whose longitudinal development and lateral distribution were simultaneously measured by the Pierre Auger Observatory. The average hadronic shower is 1.33±0.16 (1.61±0.21) times larger than predicted using the leading LHC-tuned models EPOS-LHC (QGSJetII-04), with a corresponding excess of muons.
Muons in air showers at the Pierre Auger Observatory
2015
We present the first hybrid measurement of the average muon number in air showers at ultrahigh energies, initiated by cosmic rays with zenith angles between 62° and 80°. The measurement is based on 174 hybrid events recorded simultaneously with the surface detector array and the fluorescence detector of the Pierre Auger Observatory. The muon number for each shower is derived by scaling a simulated reference profile of the lateral muon density distribution at the ground until it fits the data. A 1019eV shower with a zenith angle of 67°, which arrives at the surface detector array at an altitude of 1450 m above sea level, contains on average (2.68±0.04±0.48(sys))×107 muons with energies large…
Proton-air cross section measurement with the ARGO-YBJ cosmic ray experiment
2009
The proton-air cross section in the energy range 1-100 TeV has been measured by the ARGO-YBJ cosmic ray experiment. The analysis is based on the flux attenuation for different atmospheric depths (i.e. zenith angles) and exploits the detector capabilities of selecting the shower development stage by means of hit multiplicity, density and lateral profile measurements at ground. The effects of shower fluctuations, the contribution of heavier primaries and the uncertainties of the hadronic interaction models, have been taken into account. The results have been used to estimate the total proton-proton cross section at center of mass energies between 70 and 500 GeV, where no accelerator data are …
Muons in air showers at the Pierre Auger Observatory: Measurement of atmospheric production depth
2014
The surface detector array of the Pierre Auger Observatory provides information about the longitudinal development of the muonic component of extensive air showers. Using the timing information from the flash analog-to-digital converter traces of surface detectors far from the shower core, it is possible to reconstruct a muon production depth distribution. We characterize the goodness of this reconstruction for zenith angles around 60° and different energies of the primary particle. From these distributions, we define Xμmax as the depth along the shower axis where the production of muons reaches maximum. We explore the potentiality of Xμmax as a useful observable to infer the mass compositi…