5 research outputs found
First Probe of Sub-GeV Dark Matter Beyond the Cosmological Expectation with the COHERENT CsI Detector at the SNS
The COHERENT collaboration searched for scalar dark matter particles produced
at the Spallation Neutron Source with masses between 1 and 220~MeV/c using
a CsI[Na] scintillation detector sensitive to nuclear recoils above
9~keV. No evidence for dark matter is found and we thus place
limits on allowed parameter space. With this low-threshold detector, we are
sensitive to coherent elastic scattering between dark matter and nuclei. The
cross section for this process is orders of magnitude higher than for other
processes historically used for accelerator-based direct-detection searches so
that our small, 14.6~kg detector significantly improves on past constraints. At
peak sensitivity, we reject the flux consistent with the cosmologically
observed dark-matter concentration for all coupling constants ,
assuming a scalar dark-matter particle. We also calculate the sensitivity of
future COHERENT detectors to dark-matter signals which will ambitiously test
multiple dark-matter spin scenarios
Monitoring the SNS basement neutron background with the MARS detector
We present the analysis and results of the first dataset collected with the
MARS neutron detector deployed at the Oak Ridge National Laboratory Spallation
Neutron Source (SNS) for the purpose of monitoring and characterizing the
beam-related neutron (BRN) background for the COHERENT collaboration. MARS was
positioned next to the COH-CsI coherent elastic neutrino-nucleus scattering
detector in the SNS basement corridor. This is the basement location of closest
proximity to the SNS target and thus, of highest neutrino flux, but it is also
well shielded from the BRN flux by infill concrete and gravel. These data show
the detector registered roughly one BRN per day. Using MARS' measured detection
efficiency, the incoming BRN flux is estimated to be
for neutron energies
above ~MeV and up to a few tens of MeV. We compare our results with
previous BRN measurements in the SNS basement corridor reported by other
neutron detectors.Comment: Submitted to JINS
A D2O detector for flux normalization of a pion decay-at-rest neutrino source
We report on the technical design and expected performance of a 592 kg heavy-water-Cherenkov detector to measure the absolute neutrino flux from the pion-decay-at-rest neutrino source at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL). The detector will be located roughly 20 m from the SNS target and will measure the neutrino flux with better than 5 % statistical uncertainty in 2 years. This heavy-water detector will serve as the first module of a two-module detector system to ultimately measure the neutrino flux to 2-3 % at both the First Target Station and the planned Second Target Station of the SNS. This detector will significantly reduce a dominant systematic uncertainty for neutrino cross-section measurements at the SNS, increasing the sensitivity of searches for new physics.Y
A COHERENT constraint on leptophobic dark matter using CsI data
We use data from the COHERENT CsI[Na] scintillation detector to constrain
sub-GeV leptophobic dark matter models. This detector was built to observe
low-energy nuclear recoils from coherent elastic neutrino-nucleus scattering.
These capabilities enable searches for dark matter particles produced at the
Spallation Neutron Source mediated by a vector portal particle with masses
between 2 and 400 MeV/c. No evidence for dark matter is observed and a
limit on the mediator coupling to quarks is placed. This constraint improves
upon previous results by two orders of magnitude. This newly explored parameter
space probes the region where the dark matter relic abundance is explained by
leptophobic dark matter when the mediator mass is roughly twice the dark matter
mass. COHERENT sets the best constraint on leptophobic dark matter at these
masses