We present results of a dark matter search performed with a 0.6 kg d exposure of the DAMIC experiment at the SNOLAB underground laboratory. We measure the energy spectrum of ionization events in the ...bulk silicon of charge-coupled devices down to a signal of 60 eV electron equivalent. The data are consistent with radiogenic backgrounds, and constraints on the spin-independent WIMP-nucleon elastic-scattering cross section are accordingly placed. A region of parameter space relevant to the potential signal from the CDMS-II Si experiment is excluded using the same target for the first time. This result obtained with a limited exposure demonstrates the potential to explore the low-mass WIMP region (<10 GeV c−2) with the upcoming DAMIC100, a 100 g detector currently being installed in SNOLAB.
The CONNIE detector prototype is operating at a distance of 30 m from the core of a 3.8 GW sub(th) nuclear reactor with the goal of establishing Charge-Coupled Devices (CCD) as a new technology for ...the detection of coherent elastic neutrino-nucleus scattering. We report on the results of the engineering run with an active mass of 4 g of silicon. The CCD array is described, and the performance observed during the first year is discussed. A compact passive shield was deployed around the detector, producing an order of magnitude reduction in the background rate. The remaining background observed during the run was stable, and dominated by internal contamination in the detector packaging materials. The in-situ calibration of the detector using X-ray lines from fluorescence demonstrates good stability of the readout system. The event rates with the reactor ON and OFF are compared, and no excess is observed coming from nuclear fission at the power plant. The upper limit for the neutrino event rate is set two orders of magnitude above the expectations for the standard model. The results demonstrate the cryogenic CCD-based detector can be remotely operated at the reactor site with stable noise below 2 e super(-) RMS and stable background rates. The success of the engineering test provides a clear path for the upgraded 100 g detector to be deployed during 2016.
We present direct detection constraints on the absorption of hidden-photon dark matter with particle masses in the range 1.2-30 eV c^{-2} with the DAMIC experiment at SNOLAB. Under the assumption ...that the local dark matter is entirely constituted of hidden photons, the sensitivity to the kinetic mixing parameter κ is competitive with constraints from solar emission, reaching a minimum value of 2.2×10^{-14} at 17 eV c^{-2}. These results are the most stringent direct detection constraints on hidden-photon dark matter in the galactic halo with masses 3-12 eV c^{-2} and the first demonstration of direct experimental sensitivity to ionization signals <12 eV from dark matter interactions.
The use of biostimulants in fish diets is a promising strategy to reduce the use of antibiotics, enhance the biochemical and immune response, which contributes to improving productive yields and ...reducing economic losses. The biochemical and immune response was evaluated in juvenile red tilapia (Oreochromis mossambicus × O. niloticus), with different levels: 0 (control), 1, 2, 3, 4 and 5% chitosan in diet. 270 animals (7.53 ± 0.50 g of initial weight), distributed in a completely randomized design of 6 treatments with 3 replicates and 45 tilapia.treatment-1, were sown in 18 tanks with 90 L of water in a closed system. The juveniles were fed for 55 days with the experimental diets and at the end of the bioassay the tissue and blood plasma samples were taken. Differences were found (p<0.05) in the variables evaluated responses, where the content of lipids, triglycerides, cholesterol, carbohydrates and glucose showed higher levels (p<0.05) at lower chitosan concentrations. However, for protein content, a better response (p<0.05) was found at higher levels of chitosan in the diet. Regarding dry matter and ash, no differences were found (p˃0.05). While superoxide dismutase and leukocytes were found in higher concentration (p<0.05) when supplemented with chitosan by 3 and 4%. It was concluded that the juvenile biochemical and immune response of red tilapia was favored with dietary chitosan supplementation.
FCC Physics Opportunities Altmannshofer, W.; Arsenyev, S. A.; Aune, S. ...
The European physical journal. C, Particles and fields,
2019, Letnik:
79, Številka:
6
Journal Article, Publication
Recenzirano
Odprti dostop
We review the physics opportunities of the Future Circular Collider, covering its e
+
e
-
, pp, ep and heavy ion programmes. We describe the measurement capabilities of each FCC component, addressing ...the study of electroweak, Higgs and strong interactions, the top quark and flavour, as well as phenomena beyond the Standard Model. We highlight the synergy and complementarity of the different colliders, which will contribute to a uniquely coherent and ambitious research programme, providing an unmatchable combination of precision and sensitivity to new physics.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
DAMIC (Dark Matter in CCDs) is an experiment searching for dark matter particles employing fully-depleted charge-coupled devices. Using the bulk silicon which composes the detector as target, we ...expect to observe coherent WIMP-nucleus elastic scattering. Although located in the SNOLAB laboratory, 2 km below the surface, the CCDs are not completely free of radioactive contamination, in particular coming from radon daughters or from the detector itself. We present novel techniques for the measurement of the radioactive contamination in the bulk silicon and on the surface of DAMIC CCDs. Limits on the Uranium and Thorium contamination as well as on the cosmogenic isotope 32 Si, intrinsically present on the detector, were performed. We have obtained upper limits on the 238 TJ (232 Th) decay rate of 5 (15) kg_1 d_1 at 95% CL. Pairs of spatially correlated electron tracks expected from 32 Si-32 P and 210 Pb-210 Bi beta decays were also measured. We have found a decay rate of 80+l10 -65 kg_1 d_1 for 32 Si and an upper limit of - 35 kg-1 d-1 for 210 Pb, both at 95% CL.
The CONNIE Experiment (Coherent Neutrino Nucleus Interaction Experiment) is currently collecting reactor neutrino data to search for the undiscovered standard model process of coherent ...neutrino-nucleus scattering (CNNS). The detector is composed of a silicon target of thick, fully-depleted, low-noise CCD detectors. Results from data collected in 2015 indicate backgrounds are controlled, and allow an estimate of sensitivity to be presented for a larger scale detector. A 2016 upgrade, adding additional target mass, and reducing readout noise, has been performed, increasing the total yield of signal events by a factor of 30, and already yielding science-quality data. Low-energy nuclear calibrations have been performed, enabling calibration down to the device energy threshold. An estimate of the sensitivity expected for measuring the coherent neutrino process is presented. Future prospects with improved detector energy thresholds are estimated.
The CONNIE experiment Aguilar-Arevalo, A.; Bertou, X.; Bonifazi, C. ...
Journal of physics. Conference series,
10/2016, Letnik:
761, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The CONNIE experiment uses fully depleted, high resistivity CCDs as particle detectors in an attempt to measure for the first time the Coherent Neutrino-Nucleus Elastic Scattering of antineutrinos ...from a nuclear reactor with silicon nuclei. This talk, given at the XV Mexican Workshop on Particles and Fields (MWPF), discussed the potential of CONNIE to perform this measurement, the installation progress at the Angra dos Reis nuclear power plant, as well as the plans for future upgrades.
Neder et al discuss their study on exercise tolerance according to the definition of airflow obstruction in smokers. The clinical significance of an FEV/FVC ratio between 0.7 and the lower limit of ...normal in previous and current smokers remains highly controversial. The key issue is whether subjects in the so-called gray zone have an increased probability of airflow obstruction, a central construct for the diagnosis of chronic obstructive pulmonary disease (COPD). Apart from statistical considerations, a common approach involves a comparison of subjects with a "discordant" ratio against subjects with "concordant (positive)" (obstruction by both criteria) and "concordant (negative)" ratios (no obstruction by both criteria) vis-a-vis structural abnormalities (emphysema burden or airway disease) and negative health outcomes such as respiratory hospitalizations.
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