1,184 research outputs found
10 GeV dark matter candidates and cosmic-ray antiprotons
Recent measurements performed with some direct dark matter detection
experiments, e.g. CDMS-II and CoGENT (after DAMA/LIBRA), have unveiled a few
events compatible with weakly interacting massive particles. The preferred mass
range is around 10 GeV, with a quite large spin-independent cross section of
-. In this paper, we recall that a light dark
matter particle with dominant couplings to quarks should also generate
cosmic-ray antiprotons. Taking advantage of recent works constraining the
Galactic dark matter mass profile on the one hand and on cosmic-ray propagation
on the other hand, we point out that considering a thermal annihilation cross
section for such low mass candidates very likely results in an antiproton flux
in tension with the current data, which should be taken into account in
subsequent studies.Comment: 4 pages, 2 figures. V2: minor changes to match the published versio
'Datafication': Making sense of (big) data in a complex world
This is a pre-print of an article published in European Journal of Information Systems. The definitive publisher-authenticated version is available at the link below. Copyright @ 2013 Operational Research Society Ltd.No abstract available (Editorial
Antimatter cosmic rays from dark matter annihilation: First results from an N-body experiment
[Abridged]. We take advantage of the galaxy-like 3D dark matter map extracted
from the HORIZON Project results to calculate the positron and antiproton
fluxes from dark matter annihilation, in a model-independent approach as well
as for dark matter particle benchmarks relevant at the LHC scale (from
supersymmetric and extra-dimensional theories). Such a study is dedicated to a
better estimate of the theoretical uncertainties affecting predictions, while
the PAMELA and GLAST satellites are currently taking data which will soon
provide better observational constraints. We discuss the predictions of the
antiproton and positron fluxes, and of the positron fraction as well, as
compared to the current data. We finally discuss the limits of the Nbody
framework in describing the dark matter halo of our Galaxy.Comment: 19 pages, 9 figures. Backgrounds included and additional comments and
figures on the positron fraction. Accepted for publication in PR
Antimatter signals of singlet scalar dark matter
We consider the singlet scalar model of dark matter and study the expected
antiproton and positron signals from dark matter annihilations. The regions of
the viable parameter space of the model that are excluded by present data are
determined, as well as those regions that will be probed by the forthcoming
experiment AMS-02. In all cases, different propagation models are investigated,
and the possible enhancement due to dark matter substructures is analyzed. We
find that the antiproton signal is more easily detectable than the positron one
over the whole parameter space. For a typical propagation model and without any
boost factor, AMS-02 will be able to probe --via antiprotons-- the singlet
model of dark matter up to masses of 600 GeV. Antiprotons constitute,
therefore, a promising signal to constraint or detect the singlet scalar model.Comment: 24 pages, 8 figures. v2: minor improvements. Accepted for publication
in JCA
Antiholons in one-dimensional t-J models
Using a newly developed hybrid Monte Carlo algorithm for the nearest-neighbor
(n.n.) t-J model, we show that antiholons identified in the supersymmetric
inverse squared (IS) t-J model are clearly visible in the electron addition
spectrum of the n.n. t-J model at J=2t and also for J=0.5t, a value of
experimental relevance.Comment: 4 pages, 4 figure
Cosmic-ray antiproton constraints on light dark matter candidates
Some direct detection experiments have recently collected excess events that
could be interpreted as a dark matter (DM) signal, pointing to particles in the
10 GeV mass range. We show that scenarios in which DM can self-annihilate
with significant couplings to quarks are likely excluded by the cosmic-ray (CR)
antiproton data, provided the annihilation is S-wave dominated when DM
decouples in the early universe. These limits apply to most of supersymmetric
candidates, eg in the minimal supersymmetric standard model (MSSM) and in the
next-to-MSSM (NMSSM), and more generally to any thermal DM particle with
hadronizing annihilation final states.Comment: Contribution to the proceedings of TAUP-2011 (Munich, 5-9 IX 2011). 4
page
Scalar Multiplet Dark Matter
We perform a systematic study of the phenomenology associated to models where
the dark matter consists in the neutral component of a scalar SU(2)_L n-uplet,
up to n=7. If one includes only the pure gauge induced annihilation
cross-sections it is known that such particles provide good dark matter
candidates, leading to the observed dark matter relic abundance for a
particular value of their mass around the TeV scale. We show that these values
actually become ranges of values -which we determine- if one takes into account
the annihilations induced by the various scalar couplings appearing in these
models. This leads to predictions for both direct and indirect detection
signatures as a function of the dark matter mass within these ranges. Both can
be largely enhanced by the quartic coupling contributions. We also explain how,
if one adds right-handed neutrinos to the scalar doublet case, the results of
this analysis allow to have altogether a viable dark matter candidate,
successful generation of neutrino masses, and leptogenesis in a particularly
minimal way with all new physics at the TeV scale.Comment: 43 pages, 20 figure
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