225 research outputs found
Astrophysical Interplay in Dark Matter Searches
I discuss recent progress in dark matter searches, focusing in particular on
how rigorous modeling the dark matter distribution in the Galaxy and in its
satellite galaxies improves our interpretation of the limits on the
annihilation and elastic scattering cross sections. Looking forward to indirect
and direct searches that will operate during the next decade, I review methods
for extracting the properties of the dark matter in these experiments in the
presence of unknown Galactic model parameters.Comment: Contribution to proceedings of CETUP* workshop in Lead, South Dakota,
July 10 - August 1, 201
Kinematics of Milky Way Satellites: Mass Estimates, Rotation Limits, and Proper Motions
In the past several years high resolution kinematic data sets from Milky Way
satellite galaxies have confirmed earlier indications that these systems are
dark matter dominated objects. Further understanding of what these galaxies
reveal about cosmology and the small scale structure of dark matter relies in
large part on a more detailed interpretation of their internal kinematics. This
article discusses a likelihood formalism that extracts important quantities
from the kinematic data, including the amplitude of rotation, proper motion,
and the mass distribution. In the simplest model the projected error on the
rotational amplitude is shown to be km s with
stars from either classical or ultra-faint satellites. The galaxy Sculptor is
analyzed for the presence of a rotational signal; no significant detection of
rotation is found, and given this result limits are derived on the Sculptor
proper motion. A criteria for model selection is discussed that determines the
parameters required to describe the dark matter halo density profiles and the
stellar velocity anisotropy. Applied to four data sets with a wide range of
velocities, the likelihood is found to be more sensitive to variations in the
slope of the dark matter density profile than variations in the velocity
anisotropy. Models with variable radial velocity anisotropy are shown to be
preferred relative to those in which this quantity is constant at all radii in
the galaxy.Comment: 20 pages. To appear in Advances in Astronomy, Dwarf-Galaxy Cosmology
issu
New Constraints on Isospin-Violating Dark Matter
We derive bounds on the dark matter annihilation cross-section for low-mass
(5-20 GeV) dark matter annihilating primarily to up or down quarks, using the
Fermi-LAT bound on gamma-rays from Milky Way satellites. For models in which
dark matter-Standard Model interactions are mediated by particular contact
operators, we show that these bounds can be directly translated into bounds on
the dark matter-proton scattering cross-section. For isospin-violating dark
matter, these constraints are tight enough to begin to constrain the
parameter-space consistent with experimental signals of low-mass dark matter.
We discuss possible models that can evade these bounds.Comment: 6 pages, 2 figures, LaTeX, some clarifications and minor errors
corrected, citations adde
Galactic Searches for Dark Matter
For nearly a century, more mass has been measured in galaxies than is
contained in the luminous stars and gas. Through continual advances in
observations and theory, it has become clear that the dark matter in galaxies
is not comprised of known astronomical objects or baryonic matter, and that
identification of it is certain to reveal a profound connection between
astrophysics, cosmology, and fundamental physics. The best explanation for dark
matter is that it is in the form of a yet undiscovered particle of nature, with
experiments now gaining sensitivity to the most well-motivated particle dark
matter candidates. In this article, I review measurements of dark matter in the
Milky Way and its satellite galaxies and the status of Galactic searches for
particle dark matter using a combination of terrestrial and space-based
astroparticle detectors, and large scale astronomical surveys. I review the
limits on the dark matter annihilation and scattering cross sections that can
be extracted from both astroparticle experiments and astronomical observations,
and explore the theoretical implications of these limits. I discuss methods to
measure the properties of particle dark matter using future experiments, and
conclude by highlighting the exciting potential for dark matter searches during
the next decade, and beyond.Comment: Invited review to be submitted to Physics Reports. 116 pages of text
and figures, 26 figures, 144 pages tota
WIMP searches with gamma rays in the Fermi era: challenges, methods and results
The launch of the gamma-ray telescope Fermi Large Area Telescope (Fermi-LAT)
started a pivotal period in indirect detection of dark matter. By outperforming
expectations, for the first time a robust and stringent test of the paradigm of
weakly interacting massive particles (WIMPs) is within reach. In this paper, we
discuss astrophysical targets for WIMP detection and the challenges they
present, review the analysis tools which have been employed to tackle these
challenges, and summarize the status of constraints on and the claimed
detections in the WIMP parameter space. Methods and results will be discussed
in comparison to Imaging Air Cherenkov Telescopes. We also provide an outlook
on short term and longer term developments.Comment: 72 pages, 7 figures, Invited review for Journal of Experimental and
Theoretical Physics,v3: added a few references, addressed referee comment
Solar neutrinos with CENS and flavor-dependent radiative corrections
We examine solar neutrinos in dark matter detectors including the effects of
flavor-dependent radiative corrections to the CENS cross section. Working
within a full three-flavor framework, and including matter effects within the
Sun and Earth, detectors with thresholds keV and exposures of
ton-year could identify contributions to the cross section beyond
tree level. The differences between the cross sections for the flavors,
combined with the difference in fluxes, would provide a new and unique method
to study the muon and tau components of the solar neutrino flux.
Flavor-dependent corrections induce a small day-night asymmetry of in the event rate, which if ultimately accessible would provide
a novel probe of flavor oscillations.Comment: 18 pages, 15 figure
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