7,226 research outputs found
Prospects For Detecting Dark Matter With Neutrino Telescopes In Light Of Recent Results From Direct Detection Experiments
Direct detection dark matter experiments, lead by the CDMS collaboration,
have placed increasingly stronger constraints on the cross sections for elastic
scattering of WIMPs on nucleons. These results impact the prospects for the
indirect detection of dark matter using neutrino telescopes. With this in mind,
we revisit the prospects for detecting neutrinos produced by the annihilation
of WIMPs in the Sun. We find that the latest bounds do not seriously limit the
models most accessible to next generation kilometer-scale neutrino telescopes
such as IceCube. This is largely due to the fact that models with significant
spin-dependent couplings to protons are the least constrained and, at the same
time, the most promising because of the efficient capture of WIMPs in the Sun.
We identify models where dark matter particles are beyond the reach of any
planned direct detection experiments while within reach of neutrino telescopes.
In summary, we find that, even when contemplating recent direct detection
results, neutrino telescopes still have the opportunity to play an important as
well as complementary role in the search for particle dark matter.Comment: 13 pages, 6 figure
Distinguishing Supersymmetry From Universal Extra Dimensions or Little Higgs Models With Dark Matter Experiments
There are compelling reasons to think that new physics will appear at or
below the TeV-scale. It is not known what form this new physics will take,
however. Although The Large Hadron collider is very likely to discover new
particles associated with the TeV-scale, it may be difficult for it to
determine the nature of those particles, whether superpartners, Kaluza-Klein
modes or other states. In this article, we consider how direct and indirect
dark matter detection experiments may provide information complementary to
hadron colliders, which can be used to discriminate between supersymmetry,
models with universal extra dimensions, and Little Higgs theories. We find
that, in many scenarios, dark matter experiments can be effectively used to
distinguish between these possibilities.Comment: 23 pages, 7 figures, references added in version
Human somatic mutation assays as biomarkers of carcinogenesis.
This paper describes four assays that detect somatic gene mutations in humans: the hypoxanthine-guanine phosphoribosyl transferase assay, the glycophorin A assay, the HLA-A assay, and the sickle cell hemoglobin assay. Somatic gene mutation can be considered a biomarker of carcinogenesis, and assays for somatic mutation may assist epidemiologists in studies that attempt to identify factors associated with increased risks of cancer. Practical aspects of the use of these assays are discussed
Plasma Physics
Contains reports on three research projects.U. S. Atomic Energy Commission (Contract AT(30- 1)- 1842
Kaluza-Klein Dark Matter, Electrons and Gamma Ray Telescopes
Kaluza-Klein dark matter particles can annihilate efficiently into
electron-positron pairs, providing a discrete feature (a sharp edge) in the
cosmic spectrum at an energy equal to the particle's mass (typically
several hundred GeV to one TeV). Although this feature is probably beyond the
reach of satellite or balloon-based cosmic ray experiments (those that
distinguish the charge and mass of the primary particle), gamma ray telescopes
may provide an alternative detection method. Designed to observe very
high-energy gamma-rays, ACTs also observe the diffuse flux of electron-induced
electromagnetic showers. The GLAST satellite, designed for gamma ray astronomy,
will also observe any high energy showers (several hundred GeV and above) in
its calorimeter. We show that high-significance detections of an
electron-positron feature from Kaluza-Klein dark matter annihilations are
possible with GLAST, and also with ACTs such as HESS, VERITAS or MAGIC.Comment: 10 pages, 2 figure
Spinless photon dark matter from two universal extra dimensions
We explore the properties of dark matter in theories with two universal extra
dimensions, where the lightest Kaluza-Klein state is a spin-0 neutral particle,
representing a six-dimensional photon polarized along the extra dimensions.
Annihilation of this 'spinless photon' proceeds predominantly through Higgs
boson exchange, and is largely independent of other Kaluza-Klein particles. The
measured relic abundance sets an upper limit on the spinless photon mass of 500
GeV, which decreases to almost 200 GeV if the Higgs boson is light. The
phenomenology of this dark matter candidate is strikingly different from
Kaluza-Klein dark matter in theories with one universal extra dimension.
Elastic scattering of the spinless photon with quarks is helicity suppressed,
making its direct detection challenging, although possible at upcoming
experiments. The prospects for indirect detection with gamma rays and
antimatter are similar to those of neutralinos. The rates predicted at neutrino
telescopes are below the sensitivity of next-generation experiments.Comment: 22 pages. Figure 7 corrected, leading to improved prospects for
direct detection. Some clarifying remarks include
Food Insecurity and Eating Disorders: A Review of Emerging Evidence
Purpose of Review: This review summarizes emerging evidence for the relationship between food insecurity and eating disorder (ED) pathology, outlines priorities for future research in this area, and comments on considerations for clinical and public health practice.
Recent Findings: Among adults, food insecurity is cross-sectionally associated with higher levels of overall ED pathology, binge eating, compensatory behaviors, binge-eating disorder, and bulimia nervosa. Evidence for similar relationships among adolescents has been less robust; however, compared to studies of adults, there have been substantially fewer studies conducted in adolescents to date.
Summary: Emerging evidence consistently indicates that food insecurity is cross-sectionally associated with bulimic-spectrum ED pathology among adults. Findings emphasize the need for ED research to include marginalized populations who have historically been overlooked in the ED field. Much more research is needed to better understand the relationship between food insecurity and ED pathology and to determine effective ways to intervene
Maverick dark matter at colliders
Assuming that dark matter is a weakly interacting massive particle (WIMP)
species X produced in the early Universe as a cold thermal relic, we study the
collider signal of pp or ppbar -> XXbar + jets and its distinguishability from
standard-model background processes associated with jets and missing energy. We
assume that the WIMP is the sole particle related to dark matter within reach
of the LHC--a "maverick" particle--and that it couples to quarks through a
higher dimensional contact interaction. We simulate the WIMP final-state signal
XXbar + jet and dominant standard-model (SM) background processes and find that
the dark-matter production process results in higher energies for the colored
final state partons than do the standard-model background processes, resulting
in more QCD radiation and a higher jet multiplicity. As a consequence, the
detectable signature of maverick dark matter is an excess over standard-model
expectations of events consisting of large missing transverse energy, together
with large leading jet transverse momentum and scalar sum of the transverse
momenta of the jets. Existing Tevatron data and forthcoming LHC data can
constrain (or discover!) maverick dark matter.Comment: 11 pages, 7 figure
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