1. Deep-learning-based cosmic-ray mass reconstruction using the water-Cherenkov and scintillation detectors of AugerPrimeNiklas Langner, Andrej Filipčič, Jon Paul Lundquist, Shima Ujjani Shivashankara, Samo Stanič, Serguei Vorobiov, Danilo Zavrtanik, Marko Zavrtanik, 2023, published scientific conference contribution Abstract: At the highest energies, cosmic rays can be detected only indirectly by the extensive air showers they create upon interaction with the Earth’s atmosphere. While high-statistics measurements of the energy and arrival directions of cosmic rays can be performed with large surface detector arrays like the Pierre Auger Observatory, the determination of the cosmic-ray mass on an event-by-event basis is challenging. Meaningful physical observables in this regard include the depth of maximum of air-shower profiles, which is related to the mean free path of the cosmic ray in the atmosphere and the shower development, as well as the number of muons that rises with the
number of nucleons in a cosmic-ray particle.
In this contribution, we present an approach to determine both of these observables from combined measurements of water-Cherenkov detectors and scintillation detectors, which are part of the AugerPrime upgrade of the Observatory. To characterize the time-dependent signals of the two detectors both separately as well as in correlation to each other, we apply deep learning techniques. Transformer networks employing the attention mechanism are especially well-suited for this task. We present the utilized network concepts and apply them to simulations to determine the precision of the event-by-event mass reconstruction that can be achieved by the combined measurements of the depth of shower maximum and the number of muons.
Keywords: Pierre Auger Observatory, ultra-high energy cosmic rays, muons, extensive air showers, surface detectors, AugerPrime, deep learning techiniques
Published in RUNG: 23.01.2024; Views: 1275; Downloads: 9
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2. The number of muons measured in hybrid events detected by the Pierre Auger ObservatoryMaximilian Stadelmaier, Andrej Filipčič, Jon Paul Lundquist, Shima Ujjani Shivashankara, Samo Stanič, Serguei Vorobiov, Danilo Zavrtanik, Marko Zavrtanik, 2023, published scientific conference contribution Abstract: The number of muons produced in extensive air showers is a reliable proxy for the amount of hadron production that occurs during the shower development. It is, therefore, an important observable in the context of identifying the mass composition of ultrahigh-energy cosmic rays. Beyond LHC energies, however, hadronic multiparticle production as it occurs in air showers from ultrahigh-energy cosmic rays, is poorly understood, and currently there is little to no way to directly test it experimentally. In simulations, current models of hadronic interactions are unable to produce the average number of muons that is measured by multiple air-shower experiments. In this work, we estimate the number of muons in vertical hybrid events detected by both the fluorescence and surface detectors of the Pierre Auger Observatory above a primary energy of 3 EeV. To reconstruct the signal, we use a model of the water-Cherenkov detector responses that
is based on air-shower universality. We take into account the effect of the longitudinal shower development on the lateral distribution of the signal at the ground, as well as the primary energy estimated from the calorimetric energy deposition of the air shower. In this way, we are able to estimate the amount of muons created in vertical showers, relative to expectations from simulated showers using modern hadronic interaction models.
Keywords: ultra-high energy cosmic rays, Pierre Auger Observatory, muons, extensive air showers
Published in RUNG: 23.01.2024; Views: 1768; Downloads: 6
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3. Extraction of the Muon Signals Recorded with the Surface Detector of the Pierre Auger Observatory Using Recurrent Neural NetworksJ.M. Carceller, Andrej Filipčič, Jon Paul Lundquist, Samo Stanič, Serguei Vorobiov, Danilo Zavrtanik, Marko Zavrtanik, Lukas Zehrer, 2022, published scientific conference contribution Abstract: We present a method based on the use of Recurrent Neural Networks to
extract the muon component from the time traces registered with
water-Cherenkov detector (WCD) stations of the Surface Detector of the Pierre
Auger Observatory. The design of the WCDs does not allow to separate the
contribution of muons to the time traces obtained from the WCDs from those of
photons, electrons and positrons for all events. Separating the muon and
electromagnetic components is crucial for the determination of the nature of
the primary cosmic rays and properties of the hadronic interactions at
ultra-high energies.
We trained a neural network to extract the muon and the
electromagnetic components from the WCD traces using a large set
of simulated air showers, with around 450 000 simulated events.
For training and evaluating the performance of the neural network,
simulated events with energies between 10^18.5 eV and 10^20 eV
and zenith angles below 60 degrees were used. We also study the
performance of this method on experimental data of the Pierre
Auger Observatory and show that our predicted muon lateral
distributions agree with the parameterizations obtained by the
AGASA collaboration.
Keywords: Pierre Auger Observatory, indirect detection, surface detection, ground array, ultra-high energy, cosmic rays, muons, machine learning, recurrent neural network
Published in RUNG: 04.10.2023; Views: 1970; Downloads: 8
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4. Expected performance of the AugerPrime Radio DetectorF. Schlüter, Andrej Filipčič, Jon Paul Lundquist, Samo Stanič, Serguei Vorobiov, Danilo Zavrtanik, Marko Zavrtanik, Lukas Zehrer, 2022, published scientific conference contribution Abstract: The AugerPrime Radio Detector will significantly increase the sky coverage of mass-sensitive measurements of ultra-high energy cosmic rays with the Pierre Auger Observatory. The detection of highly inclined air showers with the world’s largest 3000km^2 radio-antenna array in coincidence with the Auger water-Cherenkov detector provides a clean separation of the electromagnetic and muonic shower components. The combination of these highly complementary measurements yields a strong sensitivity to the mass composition of cosmic rays.
We will present the first results of an end-to-end simulation study of the performance of the AugerPrime Radio Detector. The study features a complete description of the AugerPrime radio antennas and reconstruction of the properties of inclined air showers, in particular the electromagnetic energy. The performance is evaluated utilizing a comprehensive set of simulated air showers together with recorded background. The estimation of an energy- and direction-dependent aperture yields an estimation of the expected 10-year event statistics. The potential to measure the number of muons in air showers with the achieved statistics is outlined. Based on the achieved energy resolution, the potential to discriminate between different cosmic-ray primaries is presented.
Keywords: Pierre Auger Observatory, AugerPrime, indirect detection, radio detection, radio antenna array, ultra-high energy, cosmic rays, air-shower muons, composition
Published in RUNG: 04.10.2023; Views: 1472; Downloads: 7
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5. Constraining Lorentz Invariance Violation using the muon content of extensive air showers measured at the Pierre Auger ObservatoryC. Trimarelli, Andrej Filipčič, Jon Paul Lundquist, Samo Stanič, Serguei Vorobiov, Danilo Zavrtanik, Marko Zavrtanik, Lukas Zehrer, 2022, published scientific conference contribution Abstract: Lorentz symmetry requires the space-time structure to be the same for all observers, but, on the other hand, various quantum gravity theories suggest that it may be violated when approaching the Planck scale. Even a small violation of Lorentz Invariance (LI) could easily affect the Ultra High Energy Cosmic Rays (UHECRs) propagation on a cosmological scale. Moreover, at the extreme energies, like those available in the collision of UHECRs with atmosphere, one should also expect a change in the interactions and, therefore, in the development of extensive air showers. For the first time, this effect has been studied using the muon content of air showers measured at the Pierre Auger Observatory. After having introduced Lorentz Invariance Violation (LIV) as a perturbation term in the single particle dispersion relation, a library of simulated showers with different energies, primary particles and LIV strengths has been produced. Leading to a change in the energy threshold of particle decays, the modification of the energy-momentum relation allows hadronic interactions of neutral pions that contribute to the growth of the hadronic cascade. As a consequence, an increase in the number of muons and a decrease in their intrinsic fluctuations are expected. Comparing the Monte Carlo expectations with the muon fluctuation measurements from the Pierre Auger Observatory, limits on LIV parameters have been derived and presented in this contribution.
Keywords: Pierre Auger Observatory, indirect detection, surface detection, ground array, ultra-high energy, cosmic rays, muons, air showers, Lorentz violation
Published in RUNG: 02.10.2023; Views: 1584; Downloads: 7
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6. Study of muons from ultrahigh energy cosmic ray air showers measured with the Telescope Array experimentR.U. Abbasi, Jon Paul Lundquist, 2018, original scientific article Abstract: One of the uncertainties in the interpretation of ultrahigh energy cosmic ray data comes from the hadronic interaction models used for air shower Monte Carlo (MC) simulations. The number of muons observed at the ground from ultrahigh energy cosmic ray–induced air showers is expected to depend upon the hadronic interaction model. One may therefore test the hadronic interaction models by comparing the measured number of muons with the MC prediction. In this paper, we present the results of studies of muon densities in ultrahigh energy extensive air showers obtained by analyzing the signal of surface detector stations which should have high muon purity. The muon purity of a station will depend on both the inclination of the shower and the relative position of the station. In seven years’ data from the Telescope Array experiment, we find that the number of particles observed for signals with an expected muon purity of
∼65% at a lateral distance of 2000 m from the shower core is 1.72±
0.10(stat)±0.37(syst) times larger than the MC prediction value using the QGSJET II-03 model for proton-induced showers. A similar effect is also seen in comparisons with other hadronic models such as QGSJET II-04, which shows a 1.67±0.10±0.36 excess. We also studied the dependence of these excesses on lateral distances and found a slower decrease of the lateral distribution of muons in the data as compared to the MC, causing larger discrepancy at larger lateral distances.
Keywords: UHECR, cosmic rays, muons, particle physics
Published in RUNG: 30.04.2020; Views: 3260; Downloads: 0
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7. Muon counting using silicon photomultipliers in the AMIGA detector of the Pierre Auger observatoryA. Aab, Andrej Filipčič, Gašper Kukec Mezek, Ahmed Saleh, Samo Stanič, Marta Trini, Darko Veberič, Serguei Vorobiov, Lili Yang, Danilo Zavrtanik, Marko Zavrtanik, 2017, original scientific article Keywords: Pierre Auger Observatory, ultra-high energy cosmic rays (UHECR), extensive air showers (EAS), EAS muon content, Auger Muons and Infill for the Ground Array (AMIGA), scintillation modules for muon counting, silicon photomultipliers (SiPM)
Published in RUNG: 08.03.2017; Views: 5081; Downloads: 1
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8. Measurement of the water-Cherenkov detector response to inclined muons using an RPC hodoscopePedro Assis, Andrej Filipčič, Gašper Kukec Mezek, Ahmed Saleh, Samo Stanič, Marta Trini, Darko Veberič, Serguei Vorobiov, Lili Yang, Danilo Zavrtanik, Marko Zavrtanik, 2015, published scientific conference contribution Abstract: The Pierre Auger Observatory operates a hybrid detector
composed of a Fluorescence Detector and a Surface Detector
array. Water-Cherenkov detectors (WCD) are the building blocks
of the array and as such play a key role in the detection of
secondary particles at the ground. A good knowledge of the
detector response is of paramount importance to lower
systematic uncertainties and thus to increase the capability
of the experiment in determining the muon content of the
extensive air showers with a higher precision.
In this work we report on a detailed study of the detector
response to single muons as a function of their trajectories
in the WCD. A dedicated Resistive Plate Chambers (RPC)
hodoscope was built and installed around one of the detectors.
The hodoscope is formed by two stand-alone low gas flux
segmented RPC detectors with the test water-Cherenkov detector
placed in between. The segmentation of the RPC detectors is of
the order of 10 cm. The hodoscope is used to trigger and
select single muon events in different geometries. The signal
recorded in the water-Cherenkov detector and performance
estimators were studied as a function of the trajectories of
the muons and compared with a dedicated simulation.
An agreement at the percent level was found, showing that the
simulation correctly describes the tank response.
Keywords: Pierre Auger Observatory, Water-Cherenkov detectors, detector calibration, inclined cosmic ray muons, Resistive Plate Chambers (RPC) hodoscope
Published in RUNG: 03.03.2016; Views: 5961; Downloads: 201
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9. The AMIGA Muon Counters of the Pierre Auger Observatory: Performance and Studies of the Lateral Distribution FunctionBrian Wundheiler, Andrej Filipčič, Gašper Kukec Mezek, Ahmed Saleh, Samo Stanič, Marta Trini, Darko Veberič, Serguei Vorobiov, Lili Yang, Danilo Zavrtanik, Marko Zavrtanik, 2015, published scientific conference contribution Abstract: The AMIGA enhancement (Auger Muons and Infill for the Ground
Array) of the Pierre Auger Observatory consists of a 23.5 km2
infill area where air shower particles are sampled by water-
Cherenkov detectors at the surface and by 30 m2 scintillation
counters buried 2.3 m underground. The Engineering Array of
AMIGA, completed since February 2015, includes 37 scintillator
modules (290 m2) in a hexagonal layout. In this work, the muon
counting performance of the scintillation detectors is analysed
over the first 20 months of operation. Parametrisations of the
detector counting resolution and the lateral trigger
probability are presented. Finally, preliminary results on the observed muon lateral distribution function (LDF) are discussed.
Keywords: Pierre Auger Observatory, AMIGA (Auger Muons and Infill for the Ground Array) muon
counters, muon lateral distribution function (LDF)
Published in RUNG: 03.03.2016; Views: 5178; Downloads: 181
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10. Measurement of the muon content in air showers at the Pierre Auger ObservatoryLaura Collica, Andrej Filipčič, Gašper Kukec Mezek, Ahmed Saleh, Samo Stanič, Marta Trini, Darko Veberič, Serguei Vorobiov, Lili Yang, Danilo Zavrtanik, Marko Zavrtanik, 2015, published scientific conference contribution Abstract: The muon content of extensive air showers is an
observable sensitive to the primary composition and to
the hadronic interaction properties. We present here
different methods which allow us to estimate the muon number
at the ground level and the muon production depth by
exploiting the measurement of the longitudinal, lateral and
temporal distribution of particles in air showers recorded at
the Pierre Auger Observatory. The results, obtained at about
10[sup]19 eV (E[inf]CM ∼ 140 TeV center-of-mass energy for
proton primaries), are compared to the predictions
of LHC-tuned hadronic interaction models with different primary
masses and suggest a deficit in the muon content at the
ground predicted by simulations. The Pierre Auger Observatory
uses water-Cherenkov detectors to measure particle
densities at the ground and therefore has a good
sensitivity to the muon content of air showers. Moreover, due
to its hybrid design, the combination of muon measurements with
other independent mass composition analyses such as Xmax
provides additional constraints on hadronic interaction models.
Keywords: Pierre Auger Observatory, ultra-high energy cosmic rays, muons, mass composition, hadronic interactions
Published in RUNG: 03.03.2016; Views: 5635; Downloads: 221
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