Marcelo Leigui | Universidade Federal do ABC (original) (raw)
Papers by Marcelo Leigui
The Astrophysical Journal, Jul 1, 2023
A search for time-directional coincidences of ultra-high-energy (UHE) photons above 10 EeV with g... more A search for time-directional coincidences of ultra-high-energy (UHE) photons above 10 EeV with gravitational wave (GW) events from the LIGO/Virgo runs O1 to O3 is conducted with the Pierre Auger Observatory. Due to the distinctive properties of photon interactions and to the background expected from hadronic showers, a subset of the most interesting GW events is selected based on their localization quality and distance. Time periods of 1000 s around and 1 day after the GW events are analyzed. No coincidences are observed. Upper limits on the UHE photon fluence from a GW event are derived that are typically at ∼7 MeV cm−2 (time period 1000 s) and ∼35 MeV cm−2 (time period 1 day). Due to the proximity of the binary neutron star merger GW170817, the energy of the source transferred into UHE photons above 40 EeV is constrained to be less than 20% of its total GW energy. These are the first limits on UHE photons from GW sources.
Physical Review Letters, Aug 10, 2012
arXiv (Cornell University), May 26, 2023
Journal of Instrumentation, Jul 1, 2021
The Pierre Auger Observatory, at present the largest cosmic-ray observatory ever built, is instru... more The Pierre Auger Observatory, at present the largest cosmic-ray observatory ever built, is instrumented with a ground array of 1600 water-Cherenkov detectors, known as the Surface Detector (SD). The SD samples the secondary particle content (mostly photons, electrons, positrons and muons) of extensive air showers initiated by cosmic rays with energies ranging from 1017eV up to more than 1020eV. Measuring the independent contribution of the muon component to the total registered signal is crucial to enhance the capability of the Observatory to estimate the mass of the cosmic rays on an event-by-event basis. However, with the current design of the SD, it is difficult to straightforwardly separate the contributions of muons to the SD time traces from those of photons, electrons and positrons. In this paper, we present a method aimed at extracting the muon component of the time traces registered with each individual detector of the SD using Recurrent Neural Networks. We derive the performances of the method by training the neural network on simulations, in which the muon and the electromagnetic components of the traces are known. We conclude this work showing the performance of this method on experimental data of the Pierre Auger Observatory. We find that our predictions agree with the parameterizations obtained by the AGASA collaboration to describe the lateral distributions of the electromagnetic and muonic components of extensive air showers.
arXiv (Cornell University), Jun 12, 2009
Nuclear Instruments and Methods in Physics Research, Apr 1, 2011
Nucleation and Atmospheric Aerosols, 2017
Journal of Instrumentation
The rapid development of general-purpose computing on graphics processing units (GPGPU) is allowi... more The rapid development of general-purpose computing on graphics processing units (GPGPU) is allowing the implementation of highly-parallelized Monte Carlo simulation chains for particle physics experiments. This technique is particularly suitable for the simulation of a pixelated charge readout for time projection chambers, given the large number of channels that this technology employs. Here we present the first implementation of a full microphysical simulator of a liquid argon time projection chamber (LArTPC) equipped with light readout and pixelated charge readout, developed for the DUNE Near Detector. The software is implemented with an end-to-end set of GPU-optimized algorithms. The algorithms have been written in Python and translated into CUDA kernels using Numba, a just-in-time compiler for a subset of Python and NumPy instructions. The GPU implementation achieves a speed up of four orders of magnitude compared with the equivalent CPU version. The simulation of the current in...
![Research paper thumbnail of A Gaseous Argon-Based Near Detector to Enhance the Physics Capabilities of DUNE [Slides]](https://attachments.academia-assets.com/118511024/thumbnails/1.jpg)
](Snowmass Summer Meeting 2022, Seattle, WA (United States), 17-26 Jul 2022
The Astrophysical Journal
Ultra-high-energy photons with energies exceeding 1017 eV offer a wealth of connections to differ... more Ultra-high-energy photons with energies exceeding 1017 eV offer a wealth of connections to different aspects of cosmic-ray astrophysics as well as to gamma-ray and neutrino astronomy. The recent observations of photons with energies in the 1015 eV range further motivate searches for even higher-energy photons. In this paper, we present a search for photons with energies exceeding 2 × 1017 eV using about 5.5 yr of hybrid data from the low-energy extensions of the Pierre Auger Observatory. The upper limits on the integral photon flux derived here are the most stringent ones to date in the energy region between 1017 and 1018 eV.
arXiv (Cornell University), Mar 8, 2021
Journal of Instrumentation, 2022
The Deep Underground Neutrino Experiment (DUNE) is a leading-edge experiment for long-baseline ne... more The Deep Underground Neutrino Experiment (DUNE) is a leading-edge experiment for long-baseline neutrino oscillation studies, neutrino astrophysics and nucleon decay searches. ProtoDUNE-Dual Phase (DP) is a 6 × 6 × 6 m3 liquid argon time-projection-chamber (LArTPC) operated at the CERN Neutrino Platform in 2019–2020 as a prototype of the DUNE far detector. In ProtoDUNE-DP, the scintillation and electroluminescence light produced by cosmic muons in the LArTPC is collected by photomultiplier tubes placed up to 7 m away from the ionizing track. In this paper, we present the performance of the ProtoDUNE-DP photon detection system, comparing different wavelength-shifting techniques and the use of xenon-doped LAr as a promising option for future large LArTPCs. The scintillation light production and propagation processes are analyzed and compared to simulations, improving understanding of the liquid argon properties.
Journal of Cosmology and Astroparticle Physics, 2021
Journal of Instrumentation, 2020
Astroparticle Physics, 2007
Journal of Cosmology and Astroparticle Physics, 2013
Journal of Cosmology and Astroparticle Physics, May 9, 2013
The Astrophysical Journal, Jul 1, 2023
A search for time-directional coincidences of ultra-high-energy (UHE) photons above 10 EeV with g... more A search for time-directional coincidences of ultra-high-energy (UHE) photons above 10 EeV with gravitational wave (GW) events from the LIGO/Virgo runs O1 to O3 is conducted with the Pierre Auger Observatory. Due to the distinctive properties of photon interactions and to the background expected from hadronic showers, a subset of the most interesting GW events is selected based on their localization quality and distance. Time periods of 1000 s around and 1 day after the GW events are analyzed. No coincidences are observed. Upper limits on the UHE photon fluence from a GW event are derived that are typically at ∼7 MeV cm−2 (time period 1000 s) and ∼35 MeV cm−2 (time period 1 day). Due to the proximity of the binary neutron star merger GW170817, the energy of the source transferred into UHE photons above 40 EeV is constrained to be less than 20% of its total GW energy. These are the first limits on UHE photons from GW sources.
Physical Review Letters, Aug 10, 2012
arXiv (Cornell University), May 26, 2023
Journal of Instrumentation, Jul 1, 2021
The Pierre Auger Observatory, at present the largest cosmic-ray observatory ever built, is instru... more The Pierre Auger Observatory, at present the largest cosmic-ray observatory ever built, is instrumented with a ground array of 1600 water-Cherenkov detectors, known as the Surface Detector (SD). The SD samples the secondary particle content (mostly photons, electrons, positrons and muons) of extensive air showers initiated by cosmic rays with energies ranging from 1017eV up to more than 1020eV. Measuring the independent contribution of the muon component to the total registered signal is crucial to enhance the capability of the Observatory to estimate the mass of the cosmic rays on an event-by-event basis. However, with the current design of the SD, it is difficult to straightforwardly separate the contributions of muons to the SD time traces from those of photons, electrons and positrons. In this paper, we present a method aimed at extracting the muon component of the time traces registered with each individual detector of the SD using Recurrent Neural Networks. We derive the performances of the method by training the neural network on simulations, in which the muon and the electromagnetic components of the traces are known. We conclude this work showing the performance of this method on experimental data of the Pierre Auger Observatory. We find that our predictions agree with the parameterizations obtained by the AGASA collaboration to describe the lateral distributions of the electromagnetic and muonic components of extensive air showers.
arXiv (Cornell University), Jun 12, 2009
Nuclear Instruments and Methods in Physics Research, Apr 1, 2011
Nucleation and Atmospheric Aerosols, 2017
Journal of Instrumentation
The rapid development of general-purpose computing on graphics processing units (GPGPU) is allowi... more The rapid development of general-purpose computing on graphics processing units (GPGPU) is allowing the implementation of highly-parallelized Monte Carlo simulation chains for particle physics experiments. This technique is particularly suitable for the simulation of a pixelated charge readout for time projection chambers, given the large number of channels that this technology employs. Here we present the first implementation of a full microphysical simulator of a liquid argon time projection chamber (LArTPC) equipped with light readout and pixelated charge readout, developed for the DUNE Near Detector. The software is implemented with an end-to-end set of GPU-optimized algorithms. The algorithms have been written in Python and translated into CUDA kernels using Numba, a just-in-time compiler for a subset of Python and NumPy instructions. The GPU implementation achieves a speed up of four orders of magnitude compared with the equivalent CPU version. The simulation of the current in...
Snowmass Summer Meeting 2022, Seattle, WA (United States), 17-26 Jul 2022
The Astrophysical Journal
Ultra-high-energy photons with energies exceeding 1017 eV offer a wealth of connections to differ... more Ultra-high-energy photons with energies exceeding 1017 eV offer a wealth of connections to different aspects of cosmic-ray astrophysics as well as to gamma-ray and neutrino astronomy. The recent observations of photons with energies in the 1015 eV range further motivate searches for even higher-energy photons. In this paper, we present a search for photons with energies exceeding 2 × 1017 eV using about 5.5 yr of hybrid data from the low-energy extensions of the Pierre Auger Observatory. The upper limits on the integral photon flux derived here are the most stringent ones to date in the energy region between 1017 and 1018 eV.
arXiv (Cornell University), Mar 8, 2021
Journal of Instrumentation, 2022
The Deep Underground Neutrino Experiment (DUNE) is a leading-edge experiment for long-baseline ne... more The Deep Underground Neutrino Experiment (DUNE) is a leading-edge experiment for long-baseline neutrino oscillation studies, neutrino astrophysics and nucleon decay searches. ProtoDUNE-Dual Phase (DP) is a 6 × 6 × 6 m3 liquid argon time-projection-chamber (LArTPC) operated at the CERN Neutrino Platform in 2019–2020 as a prototype of the DUNE far detector. In ProtoDUNE-DP, the scintillation and electroluminescence light produced by cosmic muons in the LArTPC is collected by photomultiplier tubes placed up to 7 m away from the ionizing track. In this paper, we present the performance of the ProtoDUNE-DP photon detection system, comparing different wavelength-shifting techniques and the use of xenon-doped LAr as a promising option for future large LArTPCs. The scintillation light production and propagation processes are analyzed and compared to simulations, improving understanding of the liquid argon properties.
Journal of Cosmology and Astroparticle Physics, 2021
Journal of Instrumentation, 2020
Astroparticle Physics, 2007
Journal of Cosmology and Astroparticle Physics, 2013
Journal of Cosmology and Astroparticle Physics, May 9, 2013
The Pierre Auger Observatory is the world's largest detector ever built for detecting and studyin... more The Pierre Auger Observatory is the world's largest detector ever built for detecting and studying the ultra-high energy cosmic rays, the most energetic particles in the Universe. It is an international effort of more than one hundred institutions from 18 countries which has been taken data for more than twelve years. The observatory in Argentina consists of a hybrid detector of 1660 water Cherenkov stations covering an area of 3,000 km^2 overlooked by 27 fluorescence telescopes and arrays of radio antennas. Since 2008, it has been completed reaching an unprecedented exposure of 50,000 km^2·sr·yr. Its objectives are to probe the origin, characteristics and to study the interactions of cosmic rays with energies above 10^17 eV. Important results have been published by the collaboration in the last years about the energy spectrum, the primary mass composition, the searches for primary photons and neutrinos and studies of the anisotropy of arrival directions, among others. In this work, we report the main recent results and discuss briefly the future plans for the observatory upgrades.
PesquisABC • nº 34, 2023
Raios cósmicos são núcleos atômicos, de prótons a elementos mais pesados, que viajam pelo espaço ... more Raios cósmicos são núcleos atômicos, de prótons a elementos
mais pesados, que viajam pelo espaço quase à velocidade da luz,
transportando energias extremamente altas. Nesta pesquisa, os autores
desenvolveram uma simulação da propagação de raios cósmicos em
campos magnéticos astrofísicos.
We present a novel numerical model for the propagation of ultra-high energy cosmic rays in the ex... more We present a novel numerical model for the propagation of ultra-high energy cosmic rays in the extragalactic medium. We take into account the diffusion of ultrarelativistic charged particles under the influence of the magnetic fields, and their energy losses. The magnetic fields are considered to be coherent within spheric cells, and with smooth transitions between them. The propagator presents a very high accuracy on calculating the particle tracking, on the order of 10 −33 of relative error in energy, and 10 −5 in Larmor radius.
We present the design, and preliminary results of the LIDRAE water-Cherenkov air shower array ins... more We present the design, and preliminary results of the LIDRAE water-Cherenkov air shower array installed at UFABC (23.6 • S, 46.5 • W, 750 m a.s.l.). LIDRAE detects the particles of extensive air showers with energies exceeding 100 TeV and is able to measure the arrival direction and energy of the primary cosmic rays. The array is composed of three tanks each filled with one thousand liters of water with a large aperture photomultiplier on the top cover of each tank overlooking the water volume. The photomultipliers detect the Cherenkov light generated by the passage of ultrarelativistic charged particles through the water. The produced signals are then sent to the data acquisition electronics where they are amplified, formatted, digitized and stored. The data are recorded in single and triple coincidence modes.
The Pierre Auger Observatory is the world's largest detector ever built for detecting and studyin... more The Pierre Auger Observatory is the world's largest detector ever built for detecting and studying the ultra-high energy cosmic rays, the most energetic particles in the Universe. It is an international effort of more than one hundred institutions from 18 countries which has been taken data for more than twelve years. The observatory in Argentina consists of a hybrid detector of 1660 water Cherenkov stations-covering an area of 3, 000 km 2-overlooked by 27 fluorescence telescopes and arrays of radio antennas. Since 2008, it has been completed reaching an unprecedented exposure of 50, 000 km 2 · sr · yr. Its objectives are to probe the origin, characteristics and to study the interactions of cosmic rays with energies above 10 17 eV. Important results have been published by the collaboration in the last years about the energy spectrum, the primary mass composition, the searches for primary photons and neutrinos and studies of the anisotropy of arrival directions, among others. In this work, we report the main recent results and discuss briefly the future plans for the observatory upgrades.