89 research outputs found
Direct detection of neutralino dark mattter in non-standard cosmologies
We compute the neutralino direct detection rate in non-standard cosmological
scenarios where neutralinos account for the dark matter of the Universe.
Significant differences are found when such rates are compared with those
predicted by the standard cosmological model. For bino-like neutralinos, the
main feature is the presence of additional light (m_\chi\lesssim 40\gev) and
heavy (m_\chi\gtrsim 600\gev) neutralinos with detection rates within the
sensitivity of future dark matter experiments. For higgsino- and wino-like
neutralinos lighter than m_\chi \sim 1\tev, enhancements of more than two
orders of magnitude in the largest detection rates are observed. Thus, if dark
matter is made up of neutralinos, the prospects for their direct detection are
in general more promising than in the standard cosmology.Comment: 10 pages, 5 figure
Lepton Flavor Violation, Neutralino Dark Matter and the Reach of the LHC
We revisit the phenomenology of the Constrained MSSM with right-handed
neutrinos (CMSSMRN). A supersymmetric seesaw mechanism, generating neutrino
masses and sizable lepton flavour violating (LFV) entries is assumed to be
operative. In this scheme, we study the complementarity between the `observable
ranges' of various paths leading to the possible discovery of low energy SUSY:
the reach of the Cern Large Hadron Collider (LHC), the quest for neutralino
dark matter signals and indirect searches through LFV processes. Within the
regions of the CMSSMRN parameter space compatible with all
cosmo-phenomenological requirements, those which are expected to be probed at
the LHC will be typically also accessible to upcoming LFV experiments.
Moreover, parameter space portions featuring a heavy SUSY particle spectrum
could be well beyond LHC reach while leaving LFV searches as the only key to
get a glimpse on SUSY.Comment: 31 pages, 12 figures, LateX; v2: one reference and one comment added;
matches with published versio
The CTA aims at the Inert Doublet Model
We show that the Cherenkov Telescope Array (CTA) can realistically challenge the Inert Doublet Model, excluding its heavy regime up to dark matter masses of 800 GeV and probing a large fraction of the remaining viable parameter space at even higher masses. Two features of the Inert Doublet Model make it particularly suitable for CTA searches. First, the dark matter mass (in the heavy regime) must be larger than 500 GeV. Second, the dark matter annihilation cross section, , is always larger than the thermal one, reaching values as high as . This higher value of is the result of the unavoidable coannhilation effects that determine the relic density via thermal freeze-out in the early Universe. We find that with 100 hours of Galactic Center exposure, CTA's expected limit widely surpasses, even after the inclusion of systematic errors, current and projected bounds from Fermi-LAT and HESS on this model
Is the dark matter particle its own antiparticle?
We propose a test based on direct detection data that allows to determine if the dark matter particle is different from its antiparticle. The test requires the precise measurement of the dark matter spin-independent direct detection cross sections off different nuclei, and consists of interpreting such signals in terms of self-conjugate (particle antiparticle) dark matter to see if such interpretation is consistent. If it is not, the dark matter must be different from its antiparticle. We illustrate this procedure for two sets of target nuclei, and , identifying the regions of the parameter space where it is particularly feasible. Our results indicate that future signals in direct detection experiments, if sufficiently accurate, might be used to establish that the dark matter particle is not its own antiparticle --a major step towards the determination of the fundamental nature of the dark matter
A singlet doublet dark matter model with radiative neutrino masses
We present a detailed study of a combined singlet-doublet scalar and
singlet-doublet fermion model for dark matter. These models have only been
studied separately in the past. We show that their combination allows for the
radiative generation of neutrino masses, but that it also implies the existence
of lepton-flavour violating (LFV) processes. We first analyse the dark matter,
neutrino mass and LFV aspects separately. We then perform two random scans for
scalar dark matter imposing Higgs mass, relic density and neutrino mass
constraints, one over the full parameter space, the other over regions where
scalar-fermion coannihilations become important. In the first case, a large
part of the new parameter space is excluded by LFV, and the remaining models
will be probed by XENONnT. In the second case, direct detection cross sections
are generally too small, but a substantial part of the viable models will be
tested by future LFV experiments. Possible constraints from the LHC are also
discussed.Comment: 27 pages, 18 figures, 2 table
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
A new viable region of the inert doublet model
The inert doublet model, a minimal extension of the Standard Model by a
second Higgs doublet, is one of the simplest and most attractive scenarios that
can explain the dark matter. In this paper, we demonstrate the existence of a
new viable region of the inert doublet model featuring dark matter masses
between Mw and about 160 GeV. Along this previously overlooked region of the
parameter space, the correct relic density is obtained thanks to cancellations
between different diagrams contributing to dark matter annihilation into gauge
bosons (W+W- and ZZ). First, we explain how these cancellations come about and
show several examples illustrating the effect of the parameters of the model on
the cancellations themselves and on the predicted relic density. Then, we
perform a full scan of the new viable region and analyze it in detail by
projecting it onto several two-dimensional planes. Finally, the prospects for
the direct and the indirect detection of inert Higgs dark matter within this
new viable region are studied. We find that present direct detection bounds
already rule out a fraction of the new parameter space and that future direct
detection experiments, such as Xenon100, will easily probe the remaining part
in its entirety.Comment: 27 pages, 16 figure
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