5 research outputs found
Development of a large-mass, low-threshold detector system with simultaneous measurements of athermal phonons and scintillation light
We have combined two low-threshold detector technologies to develop a
large-mass, low-threshold detector system that simultaneously measures the
athermal phonons in a sapphire detector while an adjacent silicon high-voltage
detector detects the scintillation light from the sapphire detector. This
detector system could provide event-by-event discrimination between electron
and nuclear events due to the difference in their scintillation light yield.
While such systems with simultaneous phonon and light detection have been
demonstrated earlier with smaller detectors, our system is designed to provide
a large detector mass with high amplification for the limited scintillation
light. Future work will focus on at least an order of magnitude improvement in
the light collection efficiency by having a highly reflective detector housing
and custom phonon mask design to maximize light collection by the silicon
high-voltage detector.Comment: 6 pages, 12 figure
Testing Meson Portal Dark Sector Solutions to the MiniBooNE Anomaly at CCM
A solution to the MiniBooNE excess invoking rare three-body decays of the
charged pions and kaons to new states in the MeV mass scale was recently
proposed as a dark-sector explanation. This class of solution illuminates the
fact that, while the charged pions were focused in the target-mode run, their
decay products were isotropically suppressed in the beam-dump-mode run in which
no excess was observed. This suggests a new physics solution correlated to the
mesonic sector. We investigate an extended set of phenomenological models that
can explain the MiniBooNE excess as a dark sector solution, utilizing
long-lived particles that might be produced in the three-body decays of the
charged mesons and the two-body anomalous decays of the neutral mesons. Over a
broad set of interactions with the long-lived particles, we show that these
scenarios can be compatible with constraints from LSND, KARMEN, and MicroBooNE,
and evaluate the sensitivity of the ongoing and future data taken by the
Coherent CAPTAIN Mills experiment (CCM) to a potential discovery in this
parameter space.Comment: 15 pages, 14 figures. Planned submission for PR
Axion-Like Particles at Coherent CAPTAIN-Mills
We investigate the sensitivity of Coherent CAPTAIN-Mills (CCM), an 800 MeV
proton-beam fixed-target experiment, to axion-like particles (ALPs) coupled to
photons and electrons. Based on beam-on background estimates from the CCM
engineering run performed in 2019, we make realistic extrapolations for
background reduction based on expected shielding improvements, reduced beam
width, and analysis-based techniques for background rejection. We obtain reach
projections for two classes of signatures. ALPs coupled primarily to photons
can be produced in the tungsten target via the Primakoff process, and then
produce a gamma-ray signal in the Liquid Argon (LAr) CCM detector either via
inverse Primakoff scattering or decay to a photon pair. ALPs with significant
electron couplings have several additional production mechanisms (Compton
scattering, annihilation, ALP-bremmstrahlung) and detection modes
(inverse Compton scattering, external pair conversion, and decay to
). We show that CCM will be the first laboratory-based experiment to
constrain regions of parameter space in the ALP-photon and ALP-electron
couplings that, to date, have only been probed by astrophysical observations.
CCM will also have sensitivity to well-motivated parameter space of QCD axion
models, including the "cosmological triangle.
First Dark Matter Search Results From Coherent CAPTAIN-Mills
This paper describes the operation of the Coherent CAPTAIN-Mills (CCM)
detector located at the Lujan Neutron Science Center (LANSCE) at Los Alamos
National Laboratory (LANL). CCM is a 10-ton liquid argon (LAr) detector located
20 meters from a high flux neutron/neutrino source and is designed to search
for sterile neutrinos () and light dark matter (LDM). An engineering run
was performed in Fall 2019 to study the characteristics of the CCM120 detector
by searching for coherent scattering signals consistent with 's and LDM
resulting from and decays in the tungsten target. New parameter
space in a leptophobic dark matter model was excluded for DM masses between
and 30 MeV. The lessons learned from this run have guided the
development and construction of the new CCM200 detector that will begin
operations in 2021 and significantly improve on these searches
EXCESS workshop: Descriptions of rising low-energy spectra
International audienceMany low-threshold experiments observe sharply rising event rates of yet unknown origins below a few hundred eV, and larger than expected from known backgrounds. Due to the significant impact of this excess on the dark matter or neutrino sensitivity of these experiments, a collective effort has been started to share the knowledge about the individual observations. For this, the EXCESS Workshop was initiated. In its first iteration in June 2021, ten rare event search collaborations contributed to this initiative via talks and discussions. The contributing collaborations were CONNIE, CRESST, DAMIC, EDELWEISS, MINER, NEWS-G, NUCLEUS, RICOCHET, SENSEI and SuperCDMS. They presented data about their observed energy spectra and known backgrounds together with details about the respective measurements. In this paper, we summarize the presented information and give a comprehensive overview of the similarities and differences between the distinct measurements. The provided data is furthermore publicly available on the workshop’s data repository together with a plotting tool for visualization