146 research outputs found
X-ray lines and self-interacting dark matter
We study the correlation between a monochromatic signal from annihilating
dark matter and its self-interacting cross section. We apply our argument to a
complex scalar dark sector, where the pseudo-scalar plays the role of a warm
dark matter candidate while the scalar mediates its interaction with the
Standard Model. We combine the recent observation of the cluster Abell 3827 for
self-interacting dark matter and the constraints on the annihilation cross
section for monochromatic X-ray lines. We also confront our model to a set of
recent experimental analyses and find that such an extension can naturally
produce a monochromatic keV signal corresponding to recent observations of
Perseus or Andromeda while in the meantime predicts self-interacting cross
section of the order of as recently
claimed in the observation of the cluster Abell 3827. We also propose a way to
distinguish such models by future direct detection techniques.Comment: 11 pages, 6 figure
The Case for an EeV Gravitino
We consider the possibility that supersymmetry is broken above the
inflationary mass scale and that the only "low" energy remnant of supersymmetry
is the gravitino with mass of order the EeV scale. The gravitino in this class
of models becomes a candidate for the dark matter of the Universe. To avoid the
over-production of gravitinos from the decays of the next-to-lightest
supersymmetric particle we argue that the supersymmetric spectrum must lie
above the inflationary mass scale ( GeV). Since , we expect
EeV. Cosmological constraints then predict a relatively
large reheating temperature between and GeV.Comment: 6 pages, 1 figure. Dedicated to the memory of Pierre Binetru
Impact of Dark Matter Direct and Indirect Detection on Simplified Dark Matter Models
We discuss simple extensions of the Standard Model featuring a (fermionic)
stable DM candidate interacting with SM fermions through a mediator.
These kind of models offer a wide phenomenology but result, at the same time,
particularly manageable, given the limited number of free-parameters, and offer
a broad LHC phenomenology. We will discuss the impact Direct and Indirect Dark
Matter searches, assuming the latter to be thermal WIMPs. We will show in
particular that the combinations of the limits on the DM Spin Independent and
Spin Dependent scattering cross-section on nuclei already exclude large
portions of the parameter space favored by DM relic density, in particular if,
in addition, a DM Indirect signal, like the Galactic Center gamma-ray excess is
required.Comment: 7 pages, 2 figures. To appear as proceeding of the conference HEP-EPS
2015, Wien (Austria
SUSY Phenomenology of KKLT Flux Compactifications
We study SUSY phenomenology of the KKLT (Kachru-Kallosh-Linde-Trivedi)
scenario of string theory compactifications with fluxes. This setup leads to a
specific pattern of soft masses and distinct phenomenological properties. In
particular, it avoids the cosmological gravitino/moduli problems. Remarkably,
the model allows for the correct abundance of SUSY dark matter consistently
with all experimental constraints including the bound on the Higgs mass, b-->s
gamma, etc. This occurs for both small and large tan beta, and requires the
SUSY spectrum above 1 TeV.Comment: 23 pages, 8 figures; v2: erratum attache
Direct and Indirect Detection of Dark Matter in Heterotic Orbifold Models
We study the neutralino dark matter phenomenology in the context of effective
field theories derived from the weakly--coupled heterotic string. We consider
in particular direct detection and indirect detection with neutrino telescopes
rates. The two cases of moduli dominated and dilaton dominated SUSY breaking
lead to completely different phenomenologies. Even if in both cases relic
density constraints can be fulfilled, moduli domination generically leads to
detection rates which are much below the present and future experimental
sensitivities, whereas dilaton domination gives high detection rates accessible
to the next generation of experiments. This could make dark matter searches an
alternative way to constrain high energy fundamental parameters.Comment: 29 pages, 13 figures. Notations clarified, figures improved, typos
and english correcte
Generating X-ray lines from annihilating dark matter
We propose different scenarios where a keV dark matter annihilates to produce
a monochromatic signal. The process is generated through the exchange of a
light scalar of mass of order 300 keV - 50 MeV coupling to photon through loops
or higher dimensional operators. For natural values of the couplings and
scales, the model can generate a gamma-ray line which can fit with the recently
identified 3.5 keV X-ray line.Comment: 10 pages, 8 figure
Radiative Production of Non-thermal Dark Matter
We compare dark matter production from the thermal bath in the early universe
with its direct production through the decay of the inflaton. We show that even
if dark matter does not possess a direct coupling with the inflaton, Standard
Model loop processes may be sufficient to generate the correct relic abundance.Comment: 12 pages, 8 figure
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