541 research outputs found
First measurements of Collins and Sivers asymmetries at COMPASS
COMPASS is a fixed-target experiment on the SPS M2 beamline at CERN. Its LiD
target can be polarised both longitudinally and transversally with respect to
the longitudinally polarised 160 GeV/c muon beam. Approximately 20% of the
beam-time in 2002, 2003 and 2004 was spent in the transverse configuration,
allowing the first measurement of both the Collins and Sivers asymmetries on a
deuterium target. First results from the the transverse data of the COMPASS run
in 2002 are reported here.Comment: 4 pages, 1 figure, contribution to parallel session of BARYONS04, Oct
25-29 2004, Palaiseau, France Removed typo, corrected erroneous referenc
Kaluza-Klein Dark Matter
We propose that cold dark matter is made of Kaluza-Klein particles and
explore avenues for its detection. The lightest Kaluza-Klein state is an
excellent dark matter candidate if standard model particles propagate in extra
dimensions and Kaluza-Klein parity is conserved. We consider Kaluza-Klein gauge
bosons. In sharp contrast to the case of supersymmetric dark matter, these
annihilate to hard positrons, neutrinos and photons with unsuppressed rates.
Direct detection signals are also promising. These conclusions are generic to
bosonic dark matter candidates.Comment: 4 pages, 3 figures, discussion of spin-independent cross section
clarified, references added, published versio
Generalized Analysis of Weakly-Interacting Massive Particle Searches
We perform a generalized analysis of data from WIMP search experiments for
point-like WIMPs of arbitrary spin and general Lorenz-invariant WIMP-nucleus
interaction. We show that in the non-relativistic limit only spin-independent
(SI) and spin-dependent (SD) WIMP-nucleon interactions survive, which can be
parameterized by only five independent parameters. We explore this
five-dimensional parameter space to determine whether the annual modulation
observed in the DAMA experiment can be consistent with all other experiments.
The pure SI interaction is ruled out except for very small region of parameter
space with the WIMP mass close to 50 GeV and the ratio of the WIMP-neutron to
WIMP-proton SI couplings . For the predominantly SD
interaction, we find an upper limit to the WIMP mass of about 18 GeV, which can
only be weakened if the constraint stemming from null searches for energetic
neutrinos from WIMP annihilation the Sun is evaded. None of the regions of the
parameter space that can reconcile all WIMP search results can be easily
accommodated in the minimal supersymmetric extension of the standard model.Comment: 27 pages, 3 figure
Effects of anthropogenic habitat disturbance and Giardia duodenalis infection on a sentinel species' gut bacteria
Habitat disturbance, a common consequence of anthropogenic land use practices, creates human–animal interfaces where humans, wildlife, and domestic species can interact. These altered habitats can influence host–microbe dynamics, leading to potential downstream effects on host physiology and health. Here, we explored the effect of ecological overlap with humans and domestic species and infection with the protozoan parasite Giardia duodenalis on the bacteria of black and gold howler monkeys (Alouatta caraya), a key sentinel species, in northeastern Argentina. Fecal samples were screened for Giardia duodenalis infection using a nested PCR reaction, and the gut bacterial community was characterized using 16S rRNA gene amplicon sequencing. Habitat type was correlated with variation in A. caraya gut bacterial community composition but did not affect gut bacterial diversity. Giardia presence did not have a universal effect on A. caraya gut bacteria across habitats, perhaps due to the high infection prevalence across all habitats. However, some bacterial taxa were found to vary with Giardia infection. While A. caraya's behavioral plasticity and dietary flexibility allow them to exploit a range of habitat conditions, habitats are generally becoming more anthropogenically disturbed and, thus, less hospitable. Alterations in gut bacterial community dynamics are one possible indicator of negative health outcomes for A. caraya in these environments, since changes in host–microbe relationships due to stressors from habitat disturbance may lead to negative repercussions for host health. These dynamics are likely relevant for understanding organism responses to environmental change in other mammals.Fil: Kuthyar, Sahana. Northwestern University; Estados UnidosFil: Kowalewski, Miguel Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia". Estación Biológica de Usos Múltiples (Sede Corrientes); Argentina. University of Emory; Estados UnidosFil: Roellig, Dawn. Centers For Disease Control And Prevention. National Center For Infectious Diseases; Estados UnidosFil: Mallot, Elizabeth K. Northwestern University; Estados UnidosFil: Zeng, Yan. Northwestern University; Estados UnidosFil: Gillespie, Thomas R. University of Emory; Estados UnidosFil: Amato, Katherine. Northwestern University; Estados Unido
On dark matter search after DAMA with Ge-73
The Weakly Interacting Massive Particle (WIMP) is one of the main candidates
for the relic dark matter (DM).In the effective low-energy minimal
supersymmetric standard model (effMSSM) the neutralino-nucleon spin and scalar
cross sections in the low-mass regime were calculated. The calculated cross
sections are compared with almost all experimental currently available
exclusion curves for spin-dependent WIMP-proton and WIMP-neutron cross
sections. It is demonstrated that in general about two-orders-of-magnitude
improvement of the current DM experiment sensitivities is needed to reach the
(effMSSM) SUSY predictions. At the current level of accuracy it looks
reasonable to safely neglect sub-dominant spin WIMP-nucleon contributions
analyzing the data from spin-non-zero targets. To avoid misleading
discrepancies between data and SUSY calculations it is, however, preferable to
use a mixed spin-scalar coupling approach.This approach is applied to estimate
future prospects of experiments with the odd-neutron high-spin isotope Ge-73.
It is noticed that the DAMA evidence favors the light Higgs sector in the
effMSSM, a high event rate in a Ge-73 detector and relatively high upgoing muon
fluxes from relic neutralino annihilations in the Earth and the Sun.Comment: 29 pages, 12 figures, 124 reference
CURVACE - CURVed Artificial Compound Eyes
International audienceCURVACE aims at designing, developing, and assessing CURVed Artificial Compound Eyes, a radically novel family of vision systems. This innovative approach will provide more efficient visual abilities for embedded applications that require motion analysis in low-power and small packages. Compared to conventional cameras, artificial compound eyes will offer a much larger field of view with negligible distortion and exceptionally high temporal resolution in smaller size and weight that will fit the requirements of a wide range of applications
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