L. N. Machado
A5056561871- Neutrino Physics Research
- Astrophysics and Cosmic Phenomena
- Particle physics theoretical and experimental studies
- Dark Matter and Cosmic Phenomena
- Radiation Detection and Scintillator Technologies
- Particle Detector Development and Performance
- Philosophy and Historical Thought
- Philosophical Thought and Analysis
- Gamma-ray bursts and supernovae
- Nuclear Physics and Applications
- Nietzsche, Schopenhauer, and Hegel
- Quantum Mechanics and Applications
- Latin American Cultural Politics
- Quantum Electrodynamics and Casimir Effect
- Particle accelerators and beam dynamics
- Psychology and Mental Health
- Superconducting Materials and Applications
- Cosmology and Gravitation Theories
- Philosophy, Ethics, and Existentialism
- Religion and Society in Latin America
- Political theory and Gramsci
- Latin American social science
- Critical Theory and Philosophy
- Seventeenth-Century Political and Philosophical Thought
- Atomic and Subatomic Physics Research
University of Glasgow
2023-2024
Istituto Nazionale di Fisica Nucleare, Sezione di Napoli
2020-2024
Stony Brook University
2024
State University of New York
2024
Duke University
2023
University of California, Irvine
2023
Universidad Autónoma de Madrid
2023
University of Bern
2023
Albert Einstein College of Medicine
2023
Colorado State University
2023
An analysis of solar neutrino data from the fourth phase Super-Kamiokande (SK-IV) October 2008 to May 2018 is performed and results are presented. The observation time dataset SK-IV corresponds 2970 days total live for all four phases 5805 days. For more precise measurements, several improvements applied in this analysis: lowering acquisition threshold 2015, further reduction spallation background using neutron clustering events, energy reconstruction considering variation PMT gain. observed...
We have searched for proton decay via $p\to e^+\pi^0$ and \mu^+\pi^0$ modes with the enlarged fiducial volume data of Super-Kamiokande from April 1996 to May 2018, which corresponds 450 kton$\cdot$years exposure. accumulated about 25% more livetime detector 22.5 kton 27.2 this analysis, so that 144 data, including 78 additional has been newly analyzed. No candidates found one candidate remains in conventional it is consistent atmospheric neutrino background prediction. set lower limits on...
We report the first search result for flux of astrophysical electron antineutrinos energies O(10) MeV in gadolinium-loaded Super-Kamiokande (SK) detector. In June 2020, gadolinium was introduced to ultra-pure water SK detector order detect neutrons more efficiently. this new experimental phase, SK-Gd, we can via inverse beta decay with efficient background rejection and higher signal efficiency thanks high neutron tagging technique. paper, initial stage SK-Gd a $22.5\times552$ $\rm kton\cdot...
We report a search for cosmic-ray boosted dark matter with protons using the 0.37 megaton×years data collected at Super-Kamiokande experiment during 1996-2018 period (SKI-IV phase). searched an excess of proton recoils above atmospheric neutrino background from vicinity Galactic Center. No such is observed, and limits are calculated two reference models either constant interaction cross section or through scalar mediator. This first experimental hadrons directional information. The results...
We present a measurement of neutrino oscillation parameters with the Super-Kamiokande detector using atmospheric neutrinos from complete pure-water SK I–V (April 1996–July 2020) dataset, including events an expanded fiducial volume. The dataset corresponds to 6511.3 live days and exposure 484.2 kiloton-years. Measurements <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mi...
The first loading of gadolinium (Gd) into Super-Kamiokande in 2020 was successful, and the neutron capture efficiency on Gd reached 50%. To further increase to 75%, 26.1 tons Gd2(SO4)3⋅8H2O additionally loaded (SK) from May 31 July 4, 2022. As amount doubled compared loading, capacity powder dissolving system doubled. We also developed new batches sulfate with even reduced radioactive impurities. In addition, a more efficient screening method devised implemented evaluate these...
We searched for proton decay via $p\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{K}^{0}$ in $0.37\text{ }\text{ }\mathrm{Mton}\ifmmode\cdot\else\textperiodcentered\fi{}\mathrm{years}$ of data collected between 1996 and 2018 from the Super-Kamiokande water Cherenkov experiment. The selection criteria were defined separately ${K}_{S}^{0}$ ${K}_{L}^{0}$ channels. No significant event excess has been observed. As a result this analysis, which extends previous search by an additional $0.2\text{...
We report the first measurement of atmospheric neutrino-oxygen neutral-current quasielastic (NCQE) cross section in gadolinium-loaded Super-Kamiokande (SK) water Cherenkov detector. In June 2020, SK began a new experimental phase, named SK-Gd, by loading 0.011% mass gadolinium into ultrapure The introduction to has effect improving neutron-tagging efficiency. Using 552.2 day dataset from August 2020 2022, we measure NCQE be <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"...
Among multi-messenger observations of the next galactic core-collapse supernova, Super-Kamiokande (SK) plays a critical role in detecting emitted supernova neutrinos, determining direction to (SN), and notifying astronomical community these advance optical signal. On 2022, SK has increased gadolinium dissolved its water target (SK-Gd) achieved Gd concentration 0.033%, resulting enhanced neutron detection capability, which turn enables more accurate determination direction. Accordingly,...
Abstract Super-Kamiokande has been searching for neutrino bursts characteristic of core-collapse supernovae continuously, in real time, since the start operations 1996. The present work focuses on detecting more distant whose event rate may be too small to trigger but identified using an offline approach. analysis data collected from 2008 2018 found no evidence bursts. This establishes upper limit 0.29 yr −1 out 100 kpc at 90% C.L. For that fail explode and collapse directly black holes...
Cosmic-ray muons that enter the Super-Kamiokande detector cause hadronic showers due to spallation in water, producing neutrons and radioactive isotopes. These are a major background source for studies of MeV-scale neutrinos searches rare events. In 2020, gadolinium was introduced into ultra-pure water improve detection efficiency neutrons. this study, cosmogenic neutron yield measured using data acquired during period after loading. The found be...
Radioactivity induced by cosmic muon spallation is a dominant source of backgrounds for <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:mi mathvariant="script">O</a:mi><a:mo stretchy="false">(</a:mo><a:mn>10</a:mn><a:mtext> </a:mtext><a:mtext> </a:mtext><a:mi>MeV</a:mi><a:mo stretchy="false">)</a:mo></a:mrow></a:math> neutrino interactions in water Cherenkov detectors. In particular, it crucial to reduce measure the solar spectrum and find from distant...
Abstract In 2020, the Super-Kamiokande (SK) experiment moved to a new stage (SK-Gd) in which gadolinium (Gd) sulfate octahydrate was added water detector, enhancing efficiency detect thermal neutrons and consequently improving sensitivity low energy electron anti-neutrinos from inverse beta decay (IBD) interactions. SK-Gd has potential provide early alerts of incipient core-collapse supernovae through detection nuclear processes responsible for cooling massive stars before gravitational...
We present a measurement of neutrino oscillation parameters with the Super-Kamiokande detector using atmospheric neutrinos from complete pure-water SK I-V (April 1996-July 2020) data set, including events an expanded fiducial volume. The set corresponds to 6511.3 live days and exposure 484.2 kiloton-years. Measurements $\Delta m^2_{32}$, $\sin^2\theta_{23}$, $\sin^2 \theta_{13}$, $\delta_{CP}$, preference for mass ordering are presented alone, constraints on \theta_{13}$ reactor experiments....
We evaluate the effect of quantum electrodynamics on correlations between Dirac field modes corresponding electron-positron pairs opposite momenta generated by expansion an asymptotically flat Friedmann-Robertson-Walker (FRW) universe. The mutual information out-going is evaluated to leading order in coupling strength and compared with free case. It shown a decrease electron positron. In addition, it found that change depends how momentum distributed positron photon modes.
Radioactivity induced by cosmic muon spallation is a dominant source of backgrounds for $\mathcal{O}(10)~$MeV neutrino interactions in water Cherenkov detectors. In particular, it crucial to reduce measure the solar spectrum and find from distant supernovae. this paper we introduce new techniques locate muon-induced hadronic showers efficiently reject backgrounds. Applying these analysis with an exposure $2790\times22.5$~kton.day increases signal efficiency $12.6\%$, approximately...
RESUMO Em nosso artigo, faremos uma breve exposição sobre o capítulo XXIV ("Exame das Quatro Nobres Verdades") dos Mūlamadhyamakakārikā ("Versos fundamentais caminho do meio"), de Nāgārjuna, e buscaremos oferecer defesa nossa própria interpretação sua filosofia, comparando-a com as interpretações semântica pedagógica propostas, respectivamente, por Garfield Siderits, um lado, Ferraro, outro. Na exposição, discutiremos a relação entre vazio, cooriginação dependente verdade, apontando íntima...
The long baseline neutrino experiment T2K has successfully used Monte Carlo simulations for the flux predictions in both near and far detectors, which are essential inputs different oscillation cross section analyses. However, current simulation software is based on FLUKA no-longer maintained package GEANT3, becoming difficult to support. A replacement beam using GEANT4 development, aiming describe physical processes from primary proton interactions target decay of hadrons muons, producing...
The Super-Kamiokande (SK) experiment is a neutrino observatory located in Japan. After the loading of gadolinium sulfate octahydrate to water its detector, SK has entered new phase, known as SK-Gd. This phase characterized by significant improvement experiment's sensitivity low energy electron anti-neutrinos, thus providing more reliable data for study sources and interactions. SK-Gd potential detecting yet-unobserved neutrinos from Diffuse Supernova Neutrino Background pre-supernova (preSN)...
We present the results of charge ratio ($R$) and polarization ($P^{\mu}_{0}$) measurements using decay electron events collected from 2008 September to 2022 June by Super-Kamiokande detector. Because its underground location long operation, we performed high precision accumulating cosmic-ray muons. measured muon be $R=1.32 \pm 0.02$ $(\mathrm{stat.}{+}\mathrm{syst.})$ at $E_{\mu}\cos \theta_{\mathrm{Zenith}}=0.7^{+0.3}_{-0.2}$ $\mathrm{TeV}$, where $E_{\mu}$ is energy...
Neutrinos from very nearby supernovae, such as Betelgeuse, are expected to generate more than ten million events over 10\,s in Super-Kamokande (SK). At large event rates, the buffers of SK analog-to-digital conversion board (QBEE) will overflow, causing random loss data that is critical for understanding dynamics supernova explosion mechanism. In order solve this problem, two new DAQ modules were developed aid observation supernovae. The first these, SN module, designed save only number hit...
A search for proton decay into <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:msup><a:mi>e</a:mi><a:mo>+</a:mo></a:msup><a:mo>/</a:mo><a:msup><a:mi>μ</a:mi><a:mo>+</a:mo></a:msup></a:math> and a <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:mi>η</c:mi></c:math> meson has been performed using data from <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"><e:mrow><e:mn>0.373</e:mn><e:mtext> </e:mtext><e:mtext>...