1,998 research outputs found
Detecting dark matter using centrifuging techniques
A new and inexpensive technique for detecting self interacting dark matter in
the form of small grains in bulk matter is proposed. Depending on the
interactions with ordinary matter, dark matter grains in bulk matter may be
isolated by using a centrifuge and using ordinary matter as a filter. The case
of mirror matter interacting with ordinary matter via photon-mirror photon
kinetic mixing provides a concrete example of this type of dark matter
candidate.Comment: About 9 page
Detecting mirror matter on Earth via its thermal imprint on ordinary matter
Mirror matter type dark matter can exist on the Earth's surface, potentially
in enhanced concentrations at various anomalous impact sites. Mirror matter
fragments can draw in heat from the ordinary matter environment, radiate mirror
photons and thereby cool the surrounding ordinary matter. We quantify this
effect and suggest that it could be used to help locate mirror matter deposits.
This method, together with the centrifuge technique, seems to provide the most
promising means to experimentally detect mirror matter type dark matter in the
Earth.Comment: 9 page
Ordinary atom-mirror atom bound states: A new window on the mirror world
Mirror symmetry is a plausible candidate for a fundamental symmetry of
particle interactions which can be exactly conserved if a set of mirror
particles exist. The properties of the mirror particles seem to provide an
excellent candidate to explain the inferred dark matter of the Universe and
might also be responsible for a variety of other puzzles in particle physics,
astrophysics, meteoritics and planetary science. One such puzzle -- the
orthopositronium lifetime problem -- can be explained if there is a small
kinetic mixing of ordinary and mirror photons. We show that this kinetic mixing
implies the existence of ordinary atom - mirror atom bound states with
interesting terrestrial and astrophysical implications. We suggest that
sensitive mass spectroscopic studies of ordinary samples containing heavy
elements such as lead might reveal the presence of these bound states, as they
would appear as anomalously heavy elements. In addition to the effects of
single mirror atoms, collective effects from embedded fragments of mirror
matter (such as mirror iron microparticles) are also possible. We speculate
that such mirror matter fragments might explain a mysterious UV photon burst
observed coming from a laser irradiated lead target in a recent experiment.Comment: about 8 pages, couple of change
Have mirror micrometeorites been detected?
Slow-moving ( km/s) 'dark matter particles' have allegedly been
discovered in a recent experiment. We explore the possibility that these slow
moving dark matter particles are small mirror matter dust particles originating
from our solar system. Ways of further testing our hypothesis, including the
possibility of observing these dust particles in cryogenic detectors such as
NAUTILUS, are also discussed.Comment: Few changes, about 8 pages lon
Diurnal modulation signal from dissipative hidden sector dark matter
We consider a simple generic dissipative dark matter model: a hidden sector
featuring two dark matter particles charged under an unbroken
interaction. Previous work has shown that such a model has the potential to
explain dark matter phenomena on both large and small scales. In this
framework, the dark matter halo in spiral galaxies features nontrivial
dynamics, with the halo energy loss due to dissipative interactions balanced by
a heat source. Ordinary supernovae can potentially supply this heat provided
kinetic mixing interaction exists with strength . This
type of kinetically mixed dark matter can be probed in direct detection
experiments. Importantly, this self-interacting dark matter can be captured
within the Earth and shield a dark matter detector from the halo wind, giving
rise to a diurnal modulation effect. We estimate the size of this effect for
detectors located in the Southern hemisphere, and find that the modulation is
large () for a wide range of parameters.Comment: 12 pages, 4 figures, clarifying comments and references adde
Near infrared radiances observed by the UK C130 multi-channel radiometer during the marine stratocumulus IFO and preliminary comparison with model calculations
A preliminary analysis of some of the narrow band radiance data measured on the U.K. Meteorological Office's C130 aircraft during the marine stratocumulus intensive field observation of First ISCCP Regional Experiment (FIRE), San Diego 29 June to 18 July 1987, is presented. The data are compared with Monte Carlo calculations of the reflectance and transmittance of the cloud based upon the observed droplet size distribution. The main scientific question being addressed is whether there is any evidence of anomalous absorption within the cloud which had been observed in similar measurements (Rozenberg et al., 1974; Twomey and Cocks, 1982; Foot, 1988). The measurements also indicate the potential for remotely sensing cloud properties. The data and method of presentation discussed here clearly separates out clouds in terms of the size of the cloud droplets. All of the daytime C130 FIRE flights have been studied and are consistent with the data presented here. There appears to be no peculiarities that might arise, for example if pollution were to be a significant factor in determining cloud absorption. Variation in the inferred size parameters, r sub e, along runs are also very small
Supernova explosions, 511 keV photons, gamma ray bursts and mirror matter
There are three astroparticle physics puzzles which fire the imagination: the
origin of the ``Great Positron Producer'' in the galactic bulge, the nature of
the gamma-ray bursts central engine and the mechanism of supernova explosions.
We show that the mirror matter model has the potential to solve all three of
these puzzles in one beautifully simple strike.Comment: about 9 page
Experimental implications of mirror matter-type dark matter
Mirror matter-type dark matter is one dark matter candidate which is
particularly well motivated from high energy physics. The theoretical
motivation and experimental evidence are pedagogically reviewed, with emphasis
on the implications of recent orthopositronium experiments, the DAMA/NaI dark
matter search, anomalous meteorite events etc.Comment: about 12 pages lon
Electric Charge Quantization
Experimentally it has been known for a long time that the electric charges of
the observed particles appear to be quantized. An approach to understanding
electric charge quantization that can be used for gauge theories with explicit
factors -- such as the standard model and its variants -- is
pedagogically reviewed and discussed in this article. This approach uses the
allowed invariances of the Lagrangian and their associated anomaly cancellation
equations. We demonstrate that charge may be de-quantized in the
three-generation standard model with massless neutrinos, because differences in
family-lepton--numbers are anomaly-free. We also review the relevant
experimental limits. Our approach to charge quantization suggests that the
minimal standard model should be extended so that family-lepton--number
differences are explicitly broken. We briefly discuss some candidate extensions
(e.g. the minimal standard model augmented by Majorana right-handed neutrinos).Comment: 18 pages, LaTeX, UM-P-92/5
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