Direct Measurement of the Muon Density in Air Showers with the Pierre Auger Observatory

As part of the upgrade of the Pierre Auger Observatory, the Auger Muons and Infill for the Ground Array (AMIGA) underground muon detector extension will allow for direct muon measurements for showers falling into the SD-750 array. We optimized the AMIGA muon reconstruction procedure by introducing a geometrical correction for muons leaving a signal in multiple detector strips due to their inclined angle of incidence and deriving a new unbiased parametrization of the muon lateral distribution function. Furthermore, we defined a zenith-independent estimator ρ35 of the muon density by parametrizing the attenuation of the muonic signal due to the atmosphere and soil layer above the buried detectors and quantified the relevant systematic uncertainties for AMIGA. The analysis of one year of calibrated data recorded with the prototype array of AMIGA confirms the results of previous studies indicating a disagreement between the muon content in simulations and data.

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Determination of the invisible energy of extensive air showers from the data collected at Pierre Auger Observatory

EPJ Web of Conferences ◽

10.1051/epjconf/201921002010 ◽

2019 ◽

Vol 210 ◽

pp. 02010

Author(s):

Analisa G. Mariazzi ◽

Keyword(s):

High Energy ◽

Primary Energy ◽

Energy Scale ◽

Extensive Air Showers ◽

Pierre Auger Observatory ◽

Mass Composition ◽

Air Showers ◽

Systematic Uncertainties ◽

Muon Production ◽

The Invisible

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.

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Depth of maximum of air-shower profiles: testing the compatibility of measurements performed at the Pierre Auger Observatory and the Telescope Array experiment

EPJ Web of Conferences ◽

10.1051/epjconf/201921001009 ◽

2019 ◽

Vol 210 ◽

pp. 01009

Author(s):

Alexey Yushkov ◽

Jose Bellido ◽

John Belz ◽

Vitor de Souza ◽

William Hanlon ◽

...

Keyword(s):

Quantitative Comparison ◽

Pierre Auger Observatory ◽

Array Detector ◽

Air Showers ◽

Fluorescence Detector ◽

Telescope Array ◽

Longitudinal Development ◽

Air Shower ◽

Direct Observations ◽

Systematic Uncertainties

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.

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

EPJ Web of Conferences ◽

10.1051/epjconf/201920901042 ◽

2019 ◽

Vol 209 ◽

pp. 01042 ◽

Cited By ~ 1

Author(s):

J. M. Carceller

Keyword(s):

Energy Range ◽

Cross Section ◽

Pierre Auger Observatory ◽

Mass Composition ◽

Air Showers ◽

Arrival Times ◽

Hadronic Interactions ◽

High Energies ◽

Systematic Uncertainties ◽

Particle Arrival

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.

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