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The 96.4 day exposure of a 3 kg ultra-low noise germanium detector to the high flux of antineutrinos from a power nuclear reactor is described. A very strong preference (\\(p<1.2\\times10^{-3}\\)) for the presence of a coherent elastic neutrino-nucleus scattering (CE\\(\\nu\\)NS) component in the data is found, when compared to a background-only model. No such effect is visible in 25 days of operation during reactor outages. The best-fit CE\\(\\nu\\)NS signal is in good agreement with expectations based on a recent characterization of germanium response to sub-keV nuclear recoils. Deviations of order 60\\% from the Standard Model CE\\(\\nu\\)NS prediction can be excluded using present data. Standing uncertainties in models of germanium quenching factor, neutrino energy spectrum, and background are examined.

The coherent elastic scattering of neutrinos off nuclei has eluded detection for four decades, even though its predicted cross section is by far the largest of all low-energy neutrino couplings. This mode of interaction offers new opportunities to study neutrino properties and leads to a miniaturization of detector size, with potential technological applications. We observed this process at a 6.7σ̃ confidence level, using a low-background, 14.6-kilogram CsI[Na] scintillator exposed to the neutrino emissions from the Spallation Neutron Source at Oak Ridge National Laboratory. Characteristic signatures in energy and time, predicted by the standard model for this process, were observed in high signal-to-background conditions. Improved constraints on nonstandard neutrino interactions with quarks are derived from this initial data set.

We construct the first comprehensive radioactive background model for a dark matter search with charge-coupled devices (CCDs). We leverage the well-characterized depth and energy resolution of the DAMIC at SNOLAB detector and a detailed GEANT4-based particle-transport simulation to model both bulk and surface backgrounds from natural radioactivity down to 50 eV\\(_{\\text{ee}}\\). We fit to the energy and depth distributions of the observed ionization events to differentiate and constrain possible background sources, for example, bulk \\(^{3}\\)H from silicon cosmogenic activation and surface \\(^{210}\\)Pb from radon plate-out. We observe the bulk background rate of the DAMIC at SNOLAB CCDs to be as low as \\(3.1 \\pm 0.6\\) counts kg\\(^{-1}\\) day\\(^{-1}\\) keV\\(_{\\text{ee}}^{-1}\\), making it the most sensitive silicon dark matter detector. Finally, we discuss the properties of a statistically significant excess of events over the background model with energies below 200 eV\\(_{\\text{ee}}\\).

We present measurements of bulk radiocontaminants in the high-resistivity silicon CCDs from the DAMIC at SNOLAB experiment. We utilize the exquisite spatial resolution of CCDs to discriminate between \\(\\alpha\\) and \\(\\beta\\) decays, and to search with high efficiency for the spatially-correlated decays of various radioisotope sequences. Using spatially-correlated \\(\\beta\\) decays, we measure a bulk radioactive contamination of \\(^{32}\\)Si in the CCDs of \\(140 \\pm 30\\) \\(\\mu\\)Bq/kg, and place an upper limit on bulk \\(^{210}\\)Pb of \\(< 160~\\mu\\)Bq/kg. Using similar analyses of spatially-correlated bulk \\(\\alpha\\) decays, we set limits of \\(< 11\\) \\(\\mu\\)Bq/kg (0.9 ppt) on \\(^{238}\\)U and of \\(< 7.3\\) \\(\\mu\\)Bq/kg (1.8 ppt) on \\(^{232}\\)Th. The ability of DAMIC CCDs to identify and reject spatially-coincident backgrounds, particularly from \\(^{32}\\)Si, has significant implications for the next generation of silicon-based dark matter experiments, where \\(\\beta\\)'s from \\(^{32}\\)Si decay will likely be a dominant background. This capability demonstrates the readiness of the CCD technology to achieve kg-scale dark matter sensitivity.

We present constraints on the existence of weakly interacting massive particles (WIMPs) from an 11 kg-day target exposure of the DAMIC experiment at the SNOLAB underground laboratory. The observed energy spectrum and spatial distribution of ionization events with electron-equivalent energies \\(>\\)200 eV\\(_{\\rm ee}\\) in the DAMIC CCDs are consistent with backgrounds from natural radioactivity. An excess of ionization events is observed above the analysis threshold of 50 eV\\(_{\\rm ee}\\). While the origin of this low-energy excess requires further investigation, our data exclude spin-independent WIMP-nucleon scattering cross sections \\(\\sigma_{\\chi-n}\\) as low as \\(3\\times 10^{-41}\\) cm\\(^2\\) for WIMPs with masses \\(m_{\\chi}\\) from 7 to 10 GeV\\(c^{-2}\\) . These results are the strongest constraints from a silicon target on the existence of WIMPs with $m_{\\chi}$$<\\(9 GeV\\)c^{-2}$ and are directly relevant to any dark matter interpretation of the excess of nuclear-recoil events observed by the CDMS silicon experiment in 2013.

We report direct-detection constraints on light dark matter particles interacting with electrons. The results are based on a method that exploits the extremely low levels of leakage current of the DAMIC detector at SNOLAB of 2-6\\(\\)10\\(^-22\\) A cm\\(^-2\\). We evaluate the charge distribution of pixels that collect \\(<10~e^-\\) for contributions beyond the leakage current that may be attributed to dark matter interactions. Constraints are placed on so-far unexplored parameter space for dark matter masses between 0.6 and 100 MeV\\(c^-2\\). We also present new constraints on hidden-photon dark matter with masses in the range \\(1.2\\)-\\(30\\) eV\\(c^-2\\).

The coherent elastic scattering of neutrinos off nuclei has eluded detection for four decades, even though its predicted cross section is by far the largest of all low-energy neutrino couplings. This mode of interaction offers new opportunities to study neutrino properties and leads to a miniaturization of detector size, with potential technological applications. We observed this process at a 6.7s confidence level, using a low-background, 14.6-kilogram CsI[Na] scintillator exposed to the neutrino emissions from the Spallation Neutron Source at Oak Ridge National Laboratory. Characteristic signatures in energy and time, predicted by the standard model for this process, were observed in high signal-to-background conditions. Improved constraints on nonstandard neutrino interactions with quarks are derived from this initial data set.

The coherent elastic scattering of neutrinos off nuclei has eluded detection for four decades, even though its predicted cross section is by far the largest of all low-energy neutrino couplings. This mode of interaction offers new opportunities to study neutrino properties and leads to a miniaturization of detector size, with potential technological applications. We observed this process at a 6.7s confidence level, using a low-background, 14.6-kilogram CsI[Na] scintillator exposed to the neutrino emissions from the Spallation Neutron Source at Oak Ridge National Laboratory. Characteristic signatures in energy and time, predicted by the standard model for this process, were observed in high signal-to-background conditions. Improved constraints on nonstandard neutrino interactions with quarks are derived from this initial data set.

This release includes data and information necessary to perform independent analyses of the COHERENT result presented in Akimov et al., arXiv:1708.01294 [nucl-ex]. Data is shared in a binned, text-based format, including both \"signal\" and \"background\" regions, so that counts and associated uncertainties can be quantitatively calculated for the purpose of separate analyses. This document describes the included information and its format, offering some guidance on use of the data. Accompanying code examples show basic interaction with the data using Python.

We study the possibility of using CsI[Na] scintillators as an advantageous target for the detection of coherent elastic neutrino-nucleus scattering (CENNS), using the neutrino emissions from the SNS spallation source at Oak Ridge National Laboratory. The response of this material to low-energy nuclear recoils like those expected from this process is characterized. Backgrounds are studied using a 2 kg low-background prototype crystal in a dedicated radiation shield. The conclusion is that a planned 14 kg detector should measure approximately 550 CENNS events per year above a demonstrated \\(\\sim7\\) keVnr low-energy threshold, with a signal-to-background ratio sufficient for a first measurement of the CENNS cross-section. The cross-section for the \\(^{208}\\)Pb(\\(\\nu_{e},e^{-}\\))\\(^{208}\\)Bi reaction, of interest for future supernova neutrino detection, can be simultaneously obtained.