Publications by authors named "IF Albuquerque"

Article Synopsis
  • - The DarkSide-50 experiment searched for dark matter particles with masses below 1 GeV/c² that interact to produce electrons using a substantial exposure of low-radioactivity liquid argon.
  • - They analyzed the ionization signals to rule out certain interactions between dark matter and electrons, providing new limits on various parameters like the dark matter-electron cross section and other coupling constants.
  • - This study also established the first direct-detection constraints for keV/c² sterile neutrinos, particularly focusing on the mixing angle related to these particles.
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Dark matter elastic scattering off nuclei can result in the excitation and ionization of the recoiling atom through the so-called Migdal effect. The energy deposition from the ionization electron adds to the energy deposited by the recoiling nuclear system and allows for the detection of interactions of sub-GeV/c^{2} mass dark matter. We present new constraints for sub-GeV/c^{2} dark matter using the dual-phase liquid argon time projection chamber of the DarkSide-50 experiment with an exposure of (12 306±184)  kg d.

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Aim: The aim of the present study was to investigate the anti-inflammatory response mediated of the M1 muscarinic acetylcholine receptor (mAChR) during experimental colitis.

Material And Methods: After the induction of 6% acetic acid colitis, mice were treated with McN-A-343 0.5, 1.

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This paper presents an inexpensive and easy-to-implement voltage sequencer instrument for use in microchip capillary electrophoresis (MCE) actuation. The voltage sequencer instrument takes a 0-5 V input signal from a microcontroller and produces a reciprocally proportional voltage signal with the capability to achieve the voltages required for MCE actuation. The unit developed in this work features four independent voltage channels, measures 105 × 143 × 45 mm (width × length × height), and the cost to assemble is under 60 USD.

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Ethnopharmacological Relevance: There are many reports of pharmacological activities of extracts and fractions of different vegetable-derived products in the scientific literature and in folk medicine. Ethnopharmacological use of these products by various communities continues to be extensively explored, and they account for more than half of all medications used worldwide. Polysaccharides (PLS) extracted from plants such as Morinda Citrifolia Linn present therapeutic potential in treatment of inflammatory bowel diseases (IBD) such as ulcerative colitis (UC).

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We present new constraints on sub-GeV dark-matter particles scattering off electrons based on 6780.0 kg d of data collected with the DarkSide-50 dual-phase argon time projection chamber. This analysis uses electroluminescence signals due to ionized electrons extracted from the liquid argon target.

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We present the results of a search for dark matter weakly interacting massive particles (WIMPs) in the mass range below 20  GeV/c^{2} using a target of low-radioactivity argon with a 6786.0 kg d exposure. The data were obtained using the DarkSide-50 apparatus at Laboratori Nazionali del Gran Sasso.

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Ultrahigh energy cosmic ray air showers probe particle physics at energies beyond the reach of accelerators. Here we introduce a new method to test hadronic interaction models without relying on the absolute energy calibration, and apply it to events with primary energy 6-16 EeV (E_{CM}=110-170  TeV), whose longitudinal development and lateral distribution were simultaneously measured by the Pierre Auger Observatory. The average hadronic shower is 1.

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We measure the energy emitted by extensive air showers in the form of radio emission in the frequency range from 30 to 80 MHz. Exploiting the accurate energy scale of the Pierre Auger Observatory, we obtain a radiation energy of 15.8±0.

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Energy-dependent patterns in the arrival directions of cosmic rays are searched for using data of the Pierre Auger Observatory. We investigate local regions around the highest-energy cosmic rays with [Formula: see text] eV by analyzing cosmic rays with energies above [Formula: see text] eV arriving within an angular separation of approximately 15[Formula: see text]. We characterize the energy distributions inside these regions by two independent methods, one searching for angular dependence of energy-energy correlations and one searching for collimation of energy along the local system of principal axes of the energy distribution.

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We report a measurement of the proton-air cross section for particle production at the center-of-mass energy per nucleon of 57 TeV. This is derived from the distribution of the depths of shower maxima observed with the Pierre Auger Observatory: systematic uncertainties are studied in detail. Analyzing the tail of the distribution of the shower maxima, a proton-air cross section of [505±22(stat)(-36)(+28)(syst)] mb is found.

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We consider models where the scale of supersymmetry breaking lies between 5 x 10(6) and 5 x 10(8) GeV. In this class of theories, which includes models of mediated supersymmetry breaking, the lightest supersymmetric particle is the gravitino, and the next to lightest is typically a long-lived charged slepton with a lifetime between a microsecond and a second, depending on its mass. We investigate the production of these particles by the diffuse flux of high energy neutrinos colliding with nucleons in the Earth, and the potential for their observation in large ice or water Cerenkov detectors.

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The dark matter in the Universe might be composed of superheavy particles (mass greater, similar 10(10) GeV). These particles can be detected via nuclear recoils produced in elastic scatterings from nuclei. We estimate the observable rate of strongly interacting supermassive particles (simpzillas) in direct dark matter search experiments.

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We report on a search for the decay KL-->pi(0)e+e- carried out by the KTeV/E799 experiment at Fermilab. This decay is expected to have a significant CP violating contribution and the measurement of its branching ratio could support the Cabibbo-Kobayashi-Maskawa mechanism for CP violation or could point to new physics. Two events were observed in the 1997 data with an expected background of 1.

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We report the first observation of a manifestly CP violating effect in the K(L)-->pi(+)pi(-)e(+)e(-) decay mode. A large asymmetry was observed in the distribution of these decays in the CP-odd and T-odd angle straight phi between the decay planes of the e(+)e(-) and pi(+)pi(-) pairs in the K(L) center of mass system. After acceptance corrections, the overall asymmetry is found to be [13.

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We report on a search for the decay K(L)-->pi(0)&mgr;(+)&mgr;(-) carried out as a part of the KTeV experiment at Fermilab. This decay is expected to have a significant CP violating contribution and a direct measurement will either support the Cabibbo-Kobayashi-Maskawa mechanism for CP violation or point to new physics. Two events were observed in the 1997 data with an expected background of 0.

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