A
bstract
Oscura is a planned light-dark matter search experiment using Skipper-CCDs with a total active mass of 10 kg. As part of the detector development, the collaboration plans to build the ...Oscura Integration Test (OIT), an engineering test with 10% of the total mass. Here we discuss the early science opportunities with the OIT to search for millicharged particles (mCPs) using the NuMI beam at Fermilab. mCPs would be produced at low energies through photon-mediated processes from decays of scalar, pseudoscalar, and vector mesons, or direct Drell-Yan productions. Estimates show that the OIT would be a world-leading probe for mCPs in the ∼MeV mass range.
The Oscura Experiment Aguilar-Arevalo, Alexis; Fabricio Alcalde Bessia; Avalos, Nicolas ...
arXiv (Cornell University),
02/2022
Paper, Journal Article
Odprti dostop
The Oscura experiment will lead the search for low-mass dark matter particles using a very large array of novel silicon Charge Coupled Devices (CCDs) with a threshold of two electrons and with a ...total exposure of 30 kg-yr. The R&D effort, which began in FY20, is currently entering the design phase with the goal of being ready to start construction in late 2024. Oscura will have unprecedented sensitivity to sub-GeV dark matter particles that interact with electrons, probing dark matter-electron scattering for masses down to 500 keV and dark matter being absorbed by electrons for masses down to 1 eV. The Oscura R&D effort has made some significant progress on the main technical challenges of the experiment, of which the most significant are engaging new foundries for the fabrication of the CCD sensors, developing a cold readout solution, and understanding the experimental backgrounds.
The Coherent Neutrino-Nucleus Interaction Experiment (CONNIE) aims to detect the coherent scattering (CE\(\nu\)NS) of reactor antineutrinos off silicon nuclei using thick fully-depleted ...high-resistivity silicon CCDs. Two Skipper-CCD sensors with sub-electron readout noise capability were installed at the experiment next to the Angra-2 reactor in 2021, making CONNIE the first experiment to employ Skipper-CCDs for reactor neutrino detection. We report on the performance of the Skipper-CCDs, the new data processing and data quality selection techniques and the event selection for CE\(\nu\)NS interactions, which enable CONNIE to reach a record low detection threshold of 15 eV. The data were collected over 300 days in 2021-2022 and correspond to exposures of 14.9 g-days with the reactor-on and 3.5 g-days with the reactor-off. The difference between the reactor-on and off event rates shows no excess and yields upper limits at 95% confidence level for the neutrino interaction rates comparable with previous CONNIE limits from standard CCDs and higher exposures. Searches for new neutrino interactions beyond the Standard Model were performed, yielding an improvement on the previous CONNIE limit on a simplified model with light vector mediators. A first dark matter (DM) search by diurnal modulation was performed by CONNIE and the results represent the best limits on the DM-electron scattering cross-section, obtained by a surface-level experiment. These promising results, obtained using a very small-mass sensor, illustrate the potential of Skipper-CCDs to probe rare neutrino interactions and motivate the plans to increase the detector mass in the near future.
Oscura is a planned light-dark matter search experiment using Skipper-CCDs with a total active mass of 10 kg. As part of the detector development, the collaboration plans to build the Oscura ...Integration Test (OIT), an engineering test with 10% of the total mass. Here we discuss the early science opportunities with the OIT to search for millicharged particles (mCPs) using the NuMI beam at Fermilab. mCPs would be produced at low energies through photon-mediated processes from decays of scalar, pseudoscalar, and vector mesons, or direct Drell-Yan productions. Estimates show that the OIT would be a world-leading probe for mCPs in the MeV mass range.
L'image, présentée de façon autonome, ou associée à d'autres éléments, constitue un vecteur de plus en plus pratiqué et privilégié dans la transmission des savoirs, des connaissances et des ...informations. S'il est presque impensable de concevoir une image seule, le texte qui l'accompagne lui donnant son sens ou du moins un sens par la légende ou le commentaire, il est de plus en plus difficile d'offrir un texte sans image, du moins dans le champ de la communication. Pour couvrir ce champ nouveau, aux spécialistes qui se sont depuis toujours intéressés à l'image : historiens de l'art, de l'histoire religieuse, du cinéma, de la télévision, se sont donc joints des chercheurs spécialistes de linguistique, de sociologie, d'histoire, de littérature, de politique. Tous envisagent les rapports qui peuvent et doivent s'établir entre texte et image, dans les champs pluridisciplinaires suivants : médias, cinéma, outils pédagogiques, fiction littéraire, discours politiques et identitaires, chroniques. Ces trente-cinq contributions concernent aussi bien l'image fixe (peintures, gravures, enluminures, illustrations de manuels scolaires, bandes dessinées, publicités, graffiti) que mobile (cinéma, télévision) dans les mondes hispaniques et hispano-américains, du Moyen Âge à nos jours.
A
bstract
The CONNIE experiment is located at a distance of 30 m from the core of a commercial nuclear reactor, and has collected a 3.7 kg-day exposure using a CCD detector array sensitive to an
∼
1 ...keV threshold for the study of coherent neutrino-nucleus elastic scattering. Here we demonstrate the potential of this low-energy neutrino experiment as a probe for physics Beyond the Standard Model, by using the recently published results to constrain two simplified extensions of the Standard Model with light mediators. We compare the new limits with those obtained for the same models using neutrinos from the Spallation Neutron Source. Our new constraints represent the best limits for these simplified models among the experiments searching for CE
ν
NS for a light vector mediator with mass
M
Z
′
<
10 MeV, and for a light scalar mediator with mass
M
ϕ
<
30 MeV. These results constitute the first use of the CONNIE data as a probe for physics Beyond the Standard Model.
Sensitive and specific blood-based assays for the detection of pulmonary and extrapulmonary tuberculosis would reduce mortality associated with missed diagnoses, particularly in children. Here we ...report a nanoparticle-enhanced immunoassay read by dark-field microscopy that detects two Mycobacterium tuberculosis virulence factors (the glycolipid lipoarabinomannan and its carrier protein) on the surface of circulating extracellular vesicles. In a cohort study of 147 hospitalized and severely immunosuppressed children living with HIV, the assay detected 58 of the 78 (74%) cases of paediatric tuberculosis, 48 of the 66 (73%) cases that were missed by microbiological assays, and 8 out of 10 (80%) cases undiagnosed during the study. It also distinguished tuberculosis from latent-tuberculosis infections in non-human primates. We adapted the assay to make it portable and operable by a smartphone. With further development, the assay may facilitate the detection of tuberculosis at the point of care, particularly in resource-limited settings.
—La infección por Papillomavirus humano (VPH) es más frecuente en pacientes inmunodeprimidos, incluyendo la infección por el virus de la inmunodeficiencia humana (VIH), donde se ha estudiado ...particularmente la infección cervical por cepas genitales oncogénicas de VPH.
Hemos estudiado las características de la infección por VPH en una consulta dermatológica de pacientes infectados por el VIH, con una muestra predominante de hombres jóvenes adictos a drogas por vía parenteral (ADVP), con lesiones verrucosas anogenitales.
Las 120 tomas de 61 pacientes correspondían a 98 muestras mucosas y 22 no mucosas. La detección en raspados con torunda, principalmente de semimucosas anal y/o genital (también en casos sin lesión), se realizó tras extracción de ADN y amplificación mediante reacción en cadena de la polimerasa (PCR). La tipificación posterior se llevó a cabo mediante digestión por enzimas de restricción e hibridación con sondas específicas. Se detectaron uno o varios tipos de VPH en un 74% de las tomas mucosas de lesiones y en un 31% de las tomas mucosas sin lesión. Los tipos de VPH más encontrados han sido VPH 6 y 11 (33 muestras), frente al VPH 16 (11 muestras) o el VPH 18 (ningún caso). Encontramos tipos de alto riesgo oncogénico asociados a cifras de CD4 inferiores a 150 /mm3. Destacamos, en conclusión, la rentabilidad de la técnica del raspado de mucosas para el clínico como cribaje de infección por VPH, la elevada incidencia de VPH incluso oncogénico en localizaciones sin lesión clínica, la frecuencia de coinfecciones por varios tipos de VPH y el predominio del VPH 6 en nuestro medio.
—Human Papillomavirus (HPV) infections are more prevalent among immunodeficient individuals, including patients infected with the human immunodeficiency virus (HIV). We studied the characteristics of HPV infection among those HIV patients visiting our dermatologic clinic, most of them young males addicted to drugs and suffering from genital warts.
We collected 120 samples from 61 patients, 98 from mucosal and 22 from non-mucosal sites. HPV-DNA was isolated from swab-scraping of ano-genital mucosa (even on freelesion sites), amplified by PCR and lately tipified by analysis of restriction-fragment-length polymorphism and hybridization with type-specific probes.
At least one HPV-type was found in 74% of lesional mucosal specimens, and in 31% of non-lesional mucosal specimens. The most frequently detected specific types in our study population were HPV 6/11 (in 33 samples), versus HPV 16 (11 samples) or HPV 18 (in no sample). We also found oncogenic types associated with CD 4 levels <150/mm3.
Our findings support the effectiveness of mucosal HPV screening for clinicians, with frequent detection of virus (even oncogenic types) in lesion-free specimens, of multiple types in single samples, and of HPV 6 as the most common type in our study population.
The Coherent Neutrino-Nucleus Interaction Experiment (CONNIE) uses low-noise fully depleted charge-coupled devices (CCDs) with the goal of measuring low-energy recoils from coherent elastic ...scattering (CE\(\nu\)NS) of reactor antineutrinos with silicon nuclei and testing nonstandard neutrino interactions (NSI). We report here the first results of the detector array deployed in 2016, considering an active mass 47.6 g (8 CCDs), which is operating at a distance of 30 m from the core of the Angra 2 nuclear reactor, with a thermal power of 3.8 GW. A search for neutrino events is performed by comparing data collected with reactor on (2.1 kg-day) and reactor off (1.6 kg-day). The results show no excess in the reactor-on data, reaching the world record sensitivity down to recoil energies of about 1 keV (0.1 keV electron-equivalent). A 95% confidence level limit for new physics is established at an event rate of 40 times the one expected from the standard model at this energy scale. The results presented here provide a new window to low-energy neutrino physics, allowing one to explore for the first time the energies accessible through the low threshold of CCDs. They will lead to new constrains on NSI from the CE\(\nu\)NS of antineutrinos from nuclear reactors.
The CONNIE experiment is located at a distance of 30 m from the core of a commercial nuclear reactor, and has collected a 3.7 kg-day exposure using a CCD detector array sensitive to an \(\sim\)1 keV ...threshold for the study of coherent neutrino-nucleus elastic scattering. Here we demonstrate the potential of this low-energy neutrino experiment as a probe for physics Beyond the Standard Model, by using the recently published results to constrain two simplified extensions of the Standard Model with light mediators. We compare the new limits with those obtained for the same models using neutrinos from the Spallation Neutron Source. Our new constraints represent the best limits for these simplified models among the experiments searching for CE\(\nu\)NS for a light vector mediator with mass \(M_{Z^{\prime}}<\) 10 MeV, and for a light scalar mediator with mass \(M_{\phi}<\) 30 MeV. These results constitute the first use of the CONNIE data as a probe for physics Beyond the Standard Model.
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