scholarly journals Testing Lorentz invariance with the ultrahigh energy cosmic ray spectrum

2009 ◽  
Vol 79 (8) ◽  
Author(s):  
Xiao-Jun Bi ◽  
Zhen Cao ◽  
Ye Li ◽  
Qiang Yuan
Keyword(s):  
Lorentz Invariance ◽  
Cosmic Ray ◽  
Ultrahigh Energy

scholarly journals Investigating the influence of diffractive interactions on ultrahigh-energy extensive air showers

2018 ◽  
Vol 33 (26) ◽  
pp. 1850153 ◽  
Author(s):  
L. B. Arbeletche ◽  
V. P. Gonçalves ◽  
M. A. Müller
Keyword(s):  
Phenomenological Models ◽  
Cosmic Ray ◽  
Extensive Air Showers ◽  
Ultrahigh Energy ◽  
Air Showers ◽  
Hadronic Interactions ◽  
Air Shower ◽  
Cosmic Ray Interactions ◽  
The Impact ◽  
Elasticity Number

The understanding of the basic properties of the ultrahigh-energy extensive air showers is dependent on the description of hadronic interactions in an energy range beyond that probed by the LHC. One of the uncertainties present in the modeling of air showers is the treatment of diffractive interactions, which are dominated by nonperturbative physics and usually described by phenomenological models. These interactions are expected to affect the development of the air showers, since they provide a way of transporting substantial amounts of energy deep in the atmosphere, modifying the global characteristics of the shower profile. In this paper, we investigate the impact of diffractive interactions in the observables that can be measured in hadronic collisions at high energies and ultrahigh-energy cosmic ray interactions. We consider three distinct phenomenological models for the treatment of diffractive physics and estimate the influence of these interactions on the elasticity, number of secondaries, longitudinal air shower profiles and muon densities for proton-air and iron-air collisions at different primary energies. Our results demonstrate that even for the most recent models, diffractive events have a non-negligible effect on the observables and that the distinct approaches for these interactions, present in the phenomenological models, still are an important source of theoretical uncertainty for the description of the extensive air showers.

scholarly journals Study of muons from ultrahigh energy cosmic ray air showers measured with the Telescope Array experiment

2019 ◽  
Vol 210 ◽  
pp. 02012
Author(s):  
R. Takeishi
Keyword(s):  
Interaction Model ◽  
Cosmic Ray ◽  
Mass Composition ◽  
Ultrahigh Energy ◽  
Air Showers ◽  
Hadronic Interaction ◽  
Telescope Array ◽  
Interaction Models ◽  
Air Shower ◽  
Number Of Particles

One of the uncertainties in ultrahigh energy cosmic ray (UHECR) observation derives from the hadronic interaction model used for air shower Monte-Carlo (MC) simulations. One may test the hadronic interaction models by comparing the measured number of muons observed at the ground from UHECR induced air showers with the MC prediction. The Telescope Array (TA) is the largest experiment in the northern hemisphere observing UHECR in Utah, USA. It aims to reveal the origin of UHECRs by studying the energy spectrum, mass composition and anisotropy of cosmic rays by utilizing an array of surface detectors (SDs) and fluorescence detectors. We studied muon densities in the UHE extensive air showers by analyzing the signal of TA SD stations for highly inclined showers. On condition that the muons contribute about 65% of the total signal, the number of particles from air showers is typically 1.88 ± 0.08 (stat.) ± 0.42 (syst.) times larger than the MC prediction with the QGSJET II-03 model for proton-induced showers. The same feature was also obtained for other hadronic interaction models, such as QGSJET II-04.

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