scholarly journals UHECR mass composition from anisotropy of their arrival directions with the Telescope Array SD

2021 ◽  
Author(s):  
Mikhail Kuznetsov ◽  
Peter Tinyakov
Keyword(s):  
Mass Composition ◽  
Telescope Array ◽  
Arrival Directions

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.

scholarly journals The highest-energy cosmic-rays – the past, the present and the future

2019 ◽  
Vol 210 ◽  
pp. 00001
Author(s):  
Alan Watson
Keyword(s):  
Energy Spectrum ◽  
Cosmic Rays ◽  
Mass Distribution ◽  
Mass Composition ◽  
Future Prospects ◽  
Telescope Array ◽  
Hadronic Interactions ◽  
The Past ◽  
Shower Maximum ◽  
The Mean

The greater part of this paper is concerned with a historical discussion of the development of the search for the origins of the highest-energy cosmic-rays together with a few remarks about future prospects.Additionally, in section 6, the situation with regard to the mass composition and energy spectrum at the highest energies is discussed. It is shown that the change of the depth of shower maximum with energy above 1 EeV, measured using the Telescope Array, is in striking agreement with similar results from the Auger Observatory. This implies that either the mean mass of cosmic rays is becoming heavier above ~4 EeV or that there is a change in details of the hadronic interactions in a manner such that protons masquerade as heavier nuclei. A long-standing controversy is thus resolved: the belief that pure protons dominate the mass distribution at the highest energies is no longer tenable.

scholarly journals The Pierre Auger Observatory: Review of Latest Results and Perspectives

Universe ◽  
2018 ◽  
Vol 4 (11) ◽  
pp. 128 ◽  
Author(s):  
Dariusz Góra ◽  
Keyword(s):  
Energy Spectrum ◽  
Cosmic Rays ◽  
Detection System ◽  
Cosmic Ray ◽  
High Energy ◽  
Pierre Auger Observatory ◽  
Mass Composition ◽  
Ultra High Energy ◽  
Energy Limitation ◽  
Arrival Directions

The Pierre Auger Observatory is the world’s largest operating detection system for the observation of ultra high energy cosmic rays (UHECRs), with energies above 10 17 eV. The detector allows detailed measurements of the energy spectrum, mass composition and arrival directions of primary cosmic rays in the energy range above 10 17 eV. The data collected at the Auger Observatory over the last decade show the suppression of the cosmic ray flux at energies above 4 × 10 19 eV. However, it is still unclear if this suppression is caused by the energy limitation of their sources or by the Greisen–Zatsepin–Kuzmin (GZK) cut-off. In such a case, UHECRs would interact with the microwave background (CMB), so that particles traveling long intergalactic distances could not have energies greater than 5 × 10 19 eV. The other puzzle is the origin of UHECRs. Some clues can be drawn from studying the distribution of their arrival directions. The recently observed dipole anisotropy has an orientation that indicates an extragalactic origin of UHECRs. The Auger surface detector array is also sensitive to showers due to ultra high energy neutrinos of all flavors and photons, and recent neutrino and photon limits provided by the Auger Observatory can constrain models of the cosmogenic neutrino production and exotic scenarios of the UHECRs origin, such as the decays of super heavy, non-standard-model particles. In this paper, the recent results on measurements of the energy spectrum, mass composition and arrival directions of cosmic rays, as well as future prospects are presented.

scholarly journals Measurements of UHECR Mass Composition by Telescope Array

2019 ◽  
Vol 210 ◽  
pp. 01008
Author(s):  
William Hanlon
Keyword(s):  
Monte Carlo ◽  
Cosmic Ray ◽  
High Energy ◽  
Mass Composition ◽  
Ultra High Energy ◽  
Fluorescence Detector ◽  
Telescope Array ◽  
Second Moments ◽  
Systematic Uncertainties ◽  
Surface Detector

Telescope Array (TA) has recently published results of nearly nine years of Xmax observations providing its highest statistics measurement of ultra high energy cosmic ray (UHECR) mass composition to date for energies exceeding 1018.2 eV. This analysis measured agreement of observed data with results expected for four different single elements. Instead of relying only on the first and second moments of Xmax distributions, we employ a morphological test of agreement between data and Monte Carlo to allow for systematic uncertainties in data and in current UHECR hadronic models. Results of this latest analysis and implications of UHECR composition observed by TA are presented. TA can utilize different analysis methods to understand composition as both a crosscheck on results and as a tool to understand systematics affecting Xmax measurements. The different analysis efforts utilizing fluorescence detector stereo, surface detector and fluorescence detector hybrid, and surface detector-only, currently underway at TA performed to understand composition are also discussed.

scholarly journals Mass Composition of UHECRs from Xmax Distributions Recorded by the Pierre Auger and Telescope Array Observatories

Universe ◽  
2021 ◽  
Vol 7 (9) ◽  
pp. 321
Author(s):  
Nicusor Arsene
Keyword(s):  
Statistical Tests ◽  
High Energy ◽  
Mass Composition ◽  
Large Set ◽  
Ultra High Energy ◽  
Telescope Array ◽  
High Energy Cosmic Rays ◽  
Low Energies ◽  
The Individual ◽  
Indirect Comparisons

In this paper we infer the mass composition of the ultra high energy cosmic rays (UHECRs) from measurements of Xmax distributions recorded at the Pierre Auger (2014) and Telescope Array (TA) (2016) Observatories, by fitting them with all possible combinations of Monte Carlo (MC) templates from a large set of primary species (p, He, C, N, O, Ne, Si and Fe), as predicted by EPOS-LHC, QGSJETII-04 and Sibyll 2.1 hadronic interaction models. We use the individual fractions of nuclei reconstructed from one experiment in each energy interval to build equivalent MC Xmax distributions, which we compare with the experimental Xmax distributions of the other experiment, applying different statistical tests of compatibility. The results obtained from both experiments confirm that the mass composition of the UHECRs is dominated (≳70%) by protons and He nuclei in the energy range investigated lgE(eV) = [17.8–19.3] (Auger) and lgE(eV) = [18.2–19.0] (TA). The indirect comparisons between the Xmax distributions recorded by the two experiments show that the degree of compatibility of the two datasets is good, even excellent in some high energy intervals, especially above the ankle (lgE(eV)∼18.7). However, our study reveals that, at low energies, further effort in data analysis is required in order to harmonize the results of the two experiments.

scholarly journals Full-sky searches for anisotropies in UHECR arrival directions with the Pierre Auger Observatory and the Telescope Array

2019 ◽  
Author(s):  
Armando di Matteo ◽  
Teresa Bister ◽  
Jonathan Biteau ◽  
Lorenzo Caccianiga ◽  
Olivier Deligny ◽  
...  
Keyword(s):  
Pierre Auger Observatory ◽  
Telescope Array ◽  
Arrival Directions

RESULTS FROM THE TELESCOPE ARRAY EXPERIMENT

2010 ◽  
Vol 19 (08n10) ◽  
pp. 1275-1283
Author(s):  
◽  
H. SAGAWA
Keyword(s):  
Cosmic Rays ◽  
High Energy ◽  
Mass Composition ◽  
Ultra High Energy ◽  
Arrival Direction ◽  
Data Set ◽  
Telescope Array ◽  
High Energy Cosmic Rays ◽  
The Status ◽  
Hybrid Detector

The Telescope Array (TA) is the largest hybrid detector in the northern hemisphere, which consists of an array of surface detectors (SD) and fluorescence detectors (FD), to explore the origin of ultra-high energy cosmic rays (UHECR) by measuring energy, arrival direction, mass composition, and other characteristics of UHECRs. Here we present the status and preliminary results based on the first data set of the experiment.

scholarly journals Anisotropy in the mass composition from the Telescope Array Surface Detector data

2020 ◽  
Author(s):  
Yana Zhezher ◽  
Grigory Rubtsov ◽  
Pierre Sokolsky ◽  
Sergey Troitsky
Keyword(s):  
Mass Composition ◽  
Telescope Array ◽  
Surface Detector
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