115 research outputs found
The Luminous Convolution Model as an alternative to dark matter in spiral galaxies
The Luminous Convolution Model (LCM) demonstrates that it is possible to
predict the rotation curves of spiral galaxies directly from estimates of the
luminous matter. We consider two frame-dependent effects on the light observed
from other galaxies: relative velocity and relative curvature. With one free
parameter, we predict the rotation curves of twenty-three (23) galaxies
represented in forty-two (42) data sets. Relative curvature effects rely upon
knowledge of both the gravitational potential from luminous mass of the
emitting galaxy and the receiving galaxy, and so each emitter galaxy is
compared to four (4) different Milky Way luminous mass models. On average in
this sample, the LCM is more successful than either dark matter or modified
gravity models in fitting the observed rotation curve data.
Implications of LCM constraints on populations synthesis modeling are
discussed in this paper. This paper substantially expands the results in
arXiv:1309.7370.Comment: Implications of LCM constraints on populations synthesis modeling are
discussed in this paper. This paper substantially expands the results in
arxiv:1309.737
A Monte Carlo simulation of the Sudbury Neutrino Observatory proportional counters
The third phase of the Sudbury Neutrino Observatory (SNO) experiment added an
array of 3He proportional counters to the detector. The purpose of this Neutral
Current Detection (NCD) array was to observe neutrons resulting from
neutral-current solar neutrino-deuteron interactions. We have developed a
detailed simulation of the current pulses from the NCD array proportional
counters, from the primary neutron capture on 3He through the NCD array
signal-processing electronics. This NCD array Monte Carlo simulation was used
to model the alpha-decay background in SNO's third-phase 8B solar-neutrino
measurement.Comment: 38 pages; submitted to the New Journal of Physic
ADMX-Orpheus First Search for 70 eV Dark Photon Dark Matter: Detailed Design, Operations, and Analysis
Dark matter makes up 85% of the matter in the universe and 27% of its energy
density, but we don't know what comprises dark matter. It is possible that dark
matter may be composed of either axions or dark photons, both of which can be
detected using an ultra-sensitive microwave cavity known as a haloscope. The
haloscope employed by ADMX consists of a cylindrical cavity operating at the
TM mode and is sensitive to the QCD axion with masses of few eV.
However, this haloscope design becomes challenging to implement for higher
masses. This is because higher masses require smaller-diameter cavities,
consequently reducing the detection volume which diminishes the detected signal
power. ADMX-Orpheus mitigates this issue by operating a tunable,
dielectrically-loaded cavity at a higher-order mode, allowing the detection
volume to remain large. This paper describes the design, operation, analysis,
and results of the inaugural ADMX-Orpheus dark photon search between 65.5
eV (15.8 GHz) and 69.3 eV (16.8 GHz), as well as future directions
for axion searches and for exploring more parameter space.Comment: 21 pages, 29 figures. To be submitted to Physical Review D. arXiv
admin note: substantial text overlap with arXiv:2112.0454
Search for 70 \mu eV Dark Photon Dark Matter with a Dielectrically-Loaded Multi-Wavelength Microwave Cavity
Microwave cavities have been deployed to search for bosonic dark matter
candidates with masses of a few eV. However, the sensitivity of these
cavity detectors is limited by their volume, and the traditionally-employed
half-wavelength cavities suffer from a significant volume reduction at higher
masses. ADMX-Orpheus mitigates this issue by operating a tunable,
dielectrically-loaded cavity at a higher-order mode, which allows the detection
volume to remain large. The ADMX-Orpheus inaugural run excludes dark photon
dark matter with kinetic mixing angle between 65.5 eV
(15.8 GHz) and 69.3 eV (16.8GHz), marking the highest-frequency tunable
microwave cavity dark matter search to date.Comment: 7 pages, 5 figure, to be submitted to PR
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