68 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
Measurement of the Absolute Differential Cross Section for np Elastic Scattering at 194 MeV
A tagged medium-energy neutron beam has been used in a precise measurement of
the absolute differential cross section for np back-scattering. The results
resolve significant discrepancies within the np database concerning the angular
dependence in this regime. The experiment has determined the absolute
normalization with 1.5% uncertainty, suitable to verify constraints of
supposedly comparable precision that arise from the rest of the database in
partial wave analyses. The analysis procedures, especially those associated
with evaluation of systematic errors in the experiment, are described in detail
so that systematic uncertainties may be included in a reasonable way in
subsequent partial wave analysis fits incorporating the present results.Comment: 22 pages, 21 figures, submitted for publication in Physical Review
Measurement of the Absolute np Scattering Differential Cross Section at 194 MeV
We describe a double-scattering experiment with a novel tagged neutron beam
to measure differential cross sections for np back-scattering to better than 2%
absolute precision. The measurement focuses on angles and energies where the
cross section magnitude and angle-dependence constrain the charged pion-nucleon
coupling constant, but existing data show serious discrepancies among
themselves and with energy-dependent partial wave analyses (PWA). The present
results are in good accord with the PWA, but deviate systematically from other
recent measurements.Comment: 4 pages, 4 figure
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