scholarly journals Studies of the UHECR Mass Composition and Hadronic Interactions with the FD and SD of the Pierre Auger Observatory

2019 ◽  
Vol 209 ◽  
pp. 01042 ◽  
Author(s):  
J. M. Carceller

With data on the depth of maximum Xmax collected during more than a decade of operation of the Pierre Auger Observatory, we report on the inferences on the mass composition of UHECRs in the energy range E = 1017.2 – 1019.6 eV and on the measurements of the proton-air cross section for energies up to 1018.5 eV. We also present the results on Xmax obtained using the information on the particle arrival times recorded by the SD stations allowing us to extend the Xmax measurements up to 1020 eV. The inferences on mass composition, in particular using the data of the SD, are subject to systematic uncertainties due to uncertainties in the description of hadronic interactions at ultra-high energies. We discuss this problem with respect to the properties of the muonic component of extensive air-showers as derived from the SD data.

2019 ◽  
Vol 210 ◽  
pp. 02010
Author(s):  
Analisa G. Mariazzi ◽  

In order to get the primary energy of cosmic rays from their extensive air showers using the fluorescence detection technique, the invisible energy should be added to the measured calorimetric energy. The invisible energy is the energy carried away by particles that do not deposit all their energy in the atmosphere. It has traditionally been calculated using Monte Carlo simulations that are dependent on the assumed primary particle mass and on model predictions for neutrino and muon production. In this work the invisible energy is obtained directly from events detected by the Pierre Auger Observatory. The method applied is based on the correlation of the measurements of the muon number at the ground with the invisible energy of the showers. By using it, the systematic uncertainties related to the unknown mass composition and to the high energy hadronic interaction models are significantly reduced, improving in this way the estimation of the energy scale of the Observatory.


2019 ◽  
Vol 208 ◽  
pp. 08003 ◽  
Author(s):  
Raul R. Prado

The hybrid design of the Pierre Auger Observatory allows for the measurement of a number of properties of extensive air showers initiated by ultra-high energy cosmic rays. By comparing these measurements to predictions from air shower simulations, it is possible to both infer the cosmic ray mass composition and test hadronic interactions beyond the energies reached by accelerators. In this paper, we will present a compilation of results of air shower measurements by the Pierre Auger Observatory which are sensitive to the properties of hadronic interactions and can be used to constrain the hadronic interaction models. The inconsistencies found between the interpretation of different observables with regard to primary composition and between their measurements and simulations show that none of the currently used hadronic interaction models can provide a proper description of air showers and, in particular, of the muon production.


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.


2019 ◽  
Vol 210 ◽  
pp. 02003
Author(s):  
Takashi Sako

Two studies by the Telescope Array group related to the hadronic interaction observed with Extensive Air Showers are reviewed. (1) Inelastic p-air cross section $ \sigma _{p - air}^{inel} = 567.0 \pm 70.5\,[{\rm{stat]}}_{ - 25}^{ + 29} [{\rm{sys}}]\,{\rm{mb}} $ and total p-p cross section $ \sigma _{p - p}^{tot} = 170_{ - 44}^{ + 48} [{\rm{stat}}]_{ - 17}^{ + 19} [{\rm{sys}}]\,{\rm{mb}} $ were determined using the 5 years of TA hybrid data with one of the 3 FD stations. These results at the highest energy $ \sqrt {S_{NN} } = 95\,{\rm{TeV}} $ showed good agreements with the extrapolation from the previous measurements and model predictions. (2) The signal sizes of SD were compared between data and MC using 7 years of TA SD data in the energy range from 1018.8 eV to 1019.2 eV. It was found that the data/MC ratios exceed unity and the deviation becomes larger when the expected fraction of muon signal, defined as muon purity P, is higher. The results support the muon excess (with respect to MC) problem reported by the previous observations.


2019 ◽  
Vol 210 ◽  
pp. 01009
Author(s):  
Alexey Yushkov ◽  
Jose Bellido ◽  
John Belz ◽  
Vitor de Souza ◽  
William Hanlon ◽  
...  

At the Pierre Auger Observatory and the Telescope Array, the measurements of depths of maximum of airshower profiles, Xmax, are performed using direct observations of the longitudinal development of showers with the help of the fluorescence telescopes. Though the same detection technique is used at both installations, the straightforward comparison of the characteristics of the measured Xmax distributions is not possible due to the different approaches to the analysis of the recorded events. In this work, the Auger – Telescope Array composition working group presents a technique to compare the Xmax measurements from the Auger Observatory and the Telescope Array. Applying this technique the compatibility of the first two moments of the measured Xmax distributions is qualitatively tested for energies 1018.2 eV < E < 1019.0 eV using the recently published Telescope Array data from the Black Rock Mesa and Long Ridge fluorescence detector stations. For a quantitative comparison, simulations of air showers with EPOS-LHC, folded with effects of the Telescope Array detector, are required along with the inclusion in the analysis of the systematic uncertainties in the measurements of Xmax and the energies of the events.


2019 ◽  
Vol 210 ◽  
pp. 05011 ◽  
Author(s):  
Tim Huege ◽  

The Auger Engineering Radio Array (AERA) complements the Pierre Auger Observatory with 150 radio-antenna stations measuring in the frequency range from 30 to 80 MHz. With an instrumented area of 17 km2, the array constitutes the largest cosmic-ray radio detector built to date, allowing us to do multi-hybrid measurements of cosmic rays in the energy range of 1017 eV up to several 1018 eV. We give an overview of AERA results and discuss the significance of radio detection for the validation of the energy scale of cosmicray detectors as well as for mass-composition measurements.


1975 ◽  
Vol 53 (10) ◽  
pp. 962-967 ◽  
Author(s):  
B. Jaduszliwer ◽  
A. Nakashima ◽  
D. A. L. Paul

The total cross sections for the scattering of positrons by helium have been measured by the method of transmission in the 16 to 270 eV energy range. The experimental results are higher than those of Canter et al. but are in reasonable agreement with recent results of Griffith et al., and at high energies tend towards Born approximation calculations. The integral of the cross section over positron momentum is smaller than the sum rule estimate made by Bransden et al. A tentative value of (0.034 ± 0.017)πa02 is assigned to the positronium formation cross section at threshold.


2016 ◽  
Vol 117 (19) ◽  
Author(s):  
A. Aab ◽  
P. Abreu ◽  
M. Aglietta ◽  
E. J. Ahn ◽  
I. Al Samarai ◽  
...  

2015 ◽  
Vol 754-755 ◽  
pp. 807-811
Author(s):  
A.A. Al-Rubaiee ◽  
Uda Hashim ◽  
Mohd Khairuddin Md Arshad ◽  
A. Rahim Ruslinda ◽  
R.M. Ayub ◽  
...  

The simulation of Cherenkov light Lateral distribution function (LDF) in Extensive Air Showers (EAS) initiated primary particles such as primary calcium, argon, proton iron nuclei, neutron and nitrogen have been performed using CORSIKA program for conditions and configurations of Tunka133 EAS Cherenkov array. The simulation was fulfilled at the high energy range 1014-1016eV for four different zenith angles 0o, 10o, 15oand 30o. The results of the simulated Cherenkov light LDF are compared with the measurements of Tunka133 EAS array for the same particles and energy range mentioned above. This comparison may give the good ability to reconstruct the energy spectrum and mass composition of the primary cosmic ray particles in EAS. The main feature of the given approach consists of the possibility to make a library of Cherenkov light LDF samples which could be utilized for analysis of real events which can be detected with different EAS arrays and reconstruction of the primary cosmic rays energy spectrum and mass composition of EAS particles.


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