scholarly journals Studies of Muons in Extensive Air Showers from Ultra-High Energy Cosmic Rays Observed with the Telescope Array Surface Detector

2018 ◽  
Author(s):  
R. Takeishi ◽  
H. Sagawa ◽  
M. Fukushima ◽  
M. Takeda ◽  
T. Nonaka ◽  
...  
Keyword(s):  
Cosmic Rays ◽  
High Energy ◽  
Extensive Air Showers ◽  
Ultra High Energy ◽  
Air Showers ◽  
Telescope Array ◽  
High Energy Cosmic Rays ◽  
Surface Detector

scholarly journals Study of muons in extensive air showers from ultra-high energy cosmic rays measured with the Telescope Array experiment

2019 ◽  
Vol 208 ◽  
pp. 08004
Author(s):  
R. Takeishi
Keyword(s):  
Cosmic Rays ◽  
High Energy ◽  
Extensive Air Showers ◽  
Mass Composition ◽  
Ultra High Energy ◽  
Air Showers ◽  
Hadronic Interaction ◽  
Telescope Array ◽  
Interaction Models ◽  
High Energy Cosmic Rays

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.

scholarly journals The hadronic interaction model Sibyll 2.3c and muon production in extensive air-showers

2019 ◽  
Vol 208 ◽  
pp. 11002 ◽  
Author(s):  
Felix Riehn ◽  
Ralph Engel ◽  
Anatoli Fedynitch ◽  
Thomas K. Gaisser ◽  
Todor Stanev
Keyword(s):  
Cosmic Rays ◽  
Interaction Model ◽  
High Energy ◽  
Extensive Air Showers ◽  
Ultra High Energy ◽  
Air Showers ◽  
Hadronic Interaction ◽  
High Energy Cosmic Rays ◽  
Muon Production

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.

scholarly journals Ultra-high-energy cosmic rays mass composition studies with the Telescope Array Surface Detector data

2018 ◽  
Vol 191 ◽  
pp. 08007
Author(s):  
Yana Zhezher
Keyword(s):  
Monte Carlo ◽  
Cosmic Rays ◽  
High Energy ◽  
Atomic Mass ◽  
Mass Composition ◽  
Ultra High Energy ◽  
Telescope Array ◽  
High Energy Cosmic Rays ◽  
Comparison Results ◽  
Surface Detector

The results on ultra-high energy cosmic rays’ chemical composition based on the data from the Telescope Array surface detector are reported. The analysis is based the boosted decision tree (BDT) multivariate analysis built upon 14 observables related to both the properties of the shower front and the lateral distribution function. The multivariate classifier is trained with Monte-Carlo sets: proton-induced, which is considered as background events, and ironinduced, considered as signal events. The classifier results in a single variable ξ for data and Monte-Carlo sets, available for one-dimensional analysis. The data to Monte-Carlo comparison results in an average atomic mass of UHECR for energy range 1018:0 - 1020:0 eV. The average atomic mass of primary particles corresponds to 〈ln A〉 = 1:52± 0:08(stat.)± 0:1(syst.). The comparison with TA hybrid composition results and the other experiments is presented.

scholarly journals Observation of ultra-high energy cosmic rays with the Telescope Array experiment

2018 ◽  
Vol 182 ◽  
pp. 02122
Author(s):  
Ryuji Takeishi
Keyword(s):  
Cosmic Rays ◽  
Cosmic Ray ◽  
High Energy ◽  
Mass Composition ◽  
Ultra High Energy ◽  
Air Showers ◽  
Telescope Array ◽  
High Energy Cosmic Rays ◽  
Fluorescence Light ◽  
Hybrid Detector

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.

scholarly journals Supergalactic Structure of Multiplets with the Telescope Array Surface Detector

2019 ◽  
Vol 210 ◽  
pp. 01006 ◽  
Author(s):  
Jon Paul Lundquist ◽  
Pierre V. Sokolsky
Keyword(s):  
Magnetic Fields ◽  
Spherical Surface ◽  
High Energy ◽  
Ultra High Energy ◽  
Telescope Array ◽  
High Energy Cosmic Rays ◽  
Surface Detector ◽  
Trial Probability ◽  
Post Trial ◽  
Event Energy

Evidence of supergalactic structure of multiplets has been found for ultra-high energy cosmic rays (UHECR) with energies above 1019 eV using 7 years of data from the Telescope Array (TA) surface detector. The tested hypothesis is that UHECR sources, and intervening magnetic fields, may be correlated with the supergalactic plane, as it is a fit to the average matter density within the GZK horizon. This structure is measured by the average behavior of the strength of intermediate-scale correlations between event energy and position (multiplets). These multiplets are measured in wedge-like shapes on the spherical surface of the fieldof-view to account for uniform and random magnetic fields. The evident structure found is consistent with toy-model simulations of a supergalactic magnetic sheet and the previously published Hot/Coldspot results of TA. The post-trial probability of this feature appearing by chance, on an isotropic sky, is found by Monte Carlo simulation to be ~4.5σ.

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