43 research outputs found
Measurement of Coherent Elastic Neutrino-Nucleus Scattering from reactor antineutrinos
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 () for the presence of a coherent elastic
neutrino-nucleus scattering (CENS) 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 CENS 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 CENS prediction can be excluded using present data. Standing
uncertainties in models of germanium quenching factor, neutrino energy
spectrum, and background are examined.Comment: 6 pages, 5 figures. Data release and additional information in
ancillary file
Experimental constraints on a dark matter origin for the DAMA annual modulation effect
A claim for evidence of dark matter interactions in the DAMA experiment has
been recently reinforced. We employ a new type of germanium detector to
conclusively rule out a standard isothermal galactic halo of Weakly Interacting
Massive Particles (WIMPs) as the explanation for the annual modulation effect
leading to the claim. Bounds are similarly imposed on a suggestion that dark
pseudoscalars mightlead to the effect. We describe the sensitivity to light
dark matter particles achievable with our device, in particular to
Next-to-Minimal Supersymmetric Model candidates.Comment: v4: introduces recent results from arXiv:0807.3279 and
arXiv:0807.2926. Sensitivity to pseudoscalars is revised in light of the
first. Discussion on the subject adde
Results from a Search for Light-Mass Dark Matter with a P-type Point Contact Germanium Detector
We report on several features present in the energy spectrum from an ultra
low-noise germanium detector operated at 2,100 m.w.e. By implementing a new
technique able to reject surface events, a number of cosmogenic peaks can be
observed for the first time. We discuss several possible causes for an
irreducible excess of bulk-like events below 3 keVee, including a dark matter
candidate common to the DAMA/LIBRA annual modulation effect, the hint of a
signal in CDMS, and phenomenological predictions. Improved constraints are
placed on a cosmological origin for the DAMA/LIBRA effect.Comment: 4 pages, 4 figures. v2: submitted version. Minimal changes in
wording, one reference adde
Search for an Annual Modulation in a P-type Point Contact Germanium Dark Matter Detector
Fifteen months of cumulative CoGeNT data are examined for indications of an
annual modulation, a predicted signature of Weakly Interacting Massive Particle
(WIMP) interactions. Presently available data support the presence of a
modulated component of unknown origin, with parameters prima facie compatible
with a galactic halo composed of light-mass WIMPs. Unoptimized estimators yield
a statistical significance for a modulation of ~2.8 sigma, limited by the short
exposure.Comment: Published version, slightly expanded discussion of ROI uncertainties,
one reference adde