scholarly journals A METHOD FOR DETERMINING THE MASS COMPOSITION OF ULTRA-HIGH ENERGY COSMIC RAYS BY PREDICTING THE DEPTH OF FIRST INTERACTION OF INDIVIDUAL EXTENSIVE AIR SHOWERS

2015 ◽  
Author(s):  
Tolga Yapici
2019 ◽  
Vol 208 ◽  
pp. 08004
Author(s):  
R. Takeishi

The origin of ultra-high energy cosmic rays (UHECRs) has been a long-standing mystery. One of the uncertainties in UHECR observation derives from the hadronic interaction model used for air shower Monte-Carlo (MC) simulations. The number of muons observed at ground level from UHECR induced air showers is expected to depend upon the composition of primary cosmic rays. The MC prediction also depends on hadronic interaction models. One may test the hadronic interaction models by comparing the measured number of muons 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 UHECR 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 which should have high muon purity. A high muon purity condition is imposed that requires the geometry of the shower and relative position of the given station and implies that muons dominate the signal. 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 protons. The same feature was also obtained for other hadronic models, such as QGSJET II-04.


2019 ◽  
Vol 208 ◽  
pp. 11002 ◽  
Author(s):  
Felix Riehn ◽  
Ralph Engel ◽  
Anatoli Fedynitch ◽  
Thomas K. Gaisser ◽  
Todor Stanev

One of the applications of the hadronic interaction model Sibyll is the simulation of extensive air showers of ultra-high energy cosmic rays. In recent years it has become more and more clear that simulations do not agree with measurements when it comes to observables related to muons in air showers. We discuss the processes in Sibyll that are directly related to muon production in extensive air showers and describe their relation to shower observables.


2018 ◽  
Vol 191 ◽  
pp. 08008
Author(s):  
Gašper Kukec Mezek

Ultra-high-energy cosmic rays (UHECRs) are highly energetic particles with []EeV energies, exceeding the capabilities of man-made colliders. They hold information on extreme astrophysical processes that create them and the medium they traverse on their way towards Earth. However, their mass composition at such energies is still unclear, because data interpretation depends on our choice of high energy hadronic interaction models. With its hybrid detection method, the Pierre Auger Observatory has the possibility to detect extensive air showers with an array of surface water-Cherenkov stations (SD) and fluorescence telescopes (FD). We present recent mass composition results from the Pierre Auger Collaboration using observational parameters from SD and FD measurements. Using the full dataset of the Pierre Auger Observatory, implications on composition can be made for energies above [1017.2]eV.


2018 ◽  
Vol 182 ◽  
pp. 02122
Author(s):  
Ryuji Takeishi

The origin of ultra-high energy cosmic rays (UHECRs) has been a longstanding mystery. The Telescope Array (TA) is the largest experiment in the northern hemisphere observing UHECR in Utah, USA. It aims to reveal the origin of UHECR by studying the energy spectrum, mass composition and anisotropy of cosmic rays. TA is a hybrid detector comprised of three air fluorescence stations which measure the fluorescence light induced from cosmic ray extensive air showers, and 507 surface scintillator counters which sample charged particles from air showers on the ground. We present the cosmic ray spectrum observed with the TA experiment. We also discuss our results from measurement of the mass composition. In addition, we present the results from the analysis of anisotropy, including the excess of observed events in a region of the northern sky at the highest energy. Finally, we introduce the TAx4 experiment which quadruples TA, and the TA low energy extension (TALE) experiment.


2012 ◽  
Vol 18 ◽  
pp. 221-229
Author(s):  
◽  
J. R. T. DE MELLO NETO

We present 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 rays arrival directions in large scales and through correlation with catalogues of celestial objects. The measurement of the cross section proton-air is discussed. Finally, the mass composition is addressed with the measurements of the variation of the depth of shower maximum with energy and with the muon density at ground.


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