121 research outputs found
Galactic positrons and electrons from astrophysical sources and dark matter
A very interesting puzzle about the origin of electron and positron cosmic
rays is deduced from the latests experimental results. We model the propagation
of such cosmic rays in terms of a successfully tested two--zone propagation
model. Several theoretical uncertainties -- like ones related to propagation --
are considered to study different types of electron and positron sources: dark
matter annihilation, secondary production, and supernova remnants.Comment: 3 pages, 1 figure. Proceedings for conference "Topics in
Astroparticle and Underground Physics" (TAUP2009). Rome, July 1-5, 200
Planck-scale effects on WIMP dark matter
There exists a widely known conjecture that gravitational effects violate
global symmetries. We study the effect of global-symmetry violating
higher-dimension operators induced by Planck-scale physics on the properties of
WIMP dark matter. Using an effective description, we show that the lifetime of
the WIMP dark matter candidate can satisfy cosmological bounds under reasonable
assumptions regarding the strength of the dimension-five operators. On the
other hand, the indirect WIMP dark matter detection signal is significantly
enhanced due to new decay channels.Comment: 12 pages, 4 figures. Version accepted for publication in Frontier
Positrons from dark matter annihilation in the galactic halo: uncertainties
Indirect detection signals from dark matter annihilation are studied in the
positron channel. We discuss in detail the positron propagation inside the
galactic medium: we present novel solutions of the diffusion and propagation
equations and we focus on the determination of the astrophysical uncertainties
which affect the positron dark matter signal. We show that, especially in the
low energy tail of the positron spectra at Earth, the uncertainty is sizeable
and we quantify the effect. Comparison of our predictions with current
available and foreseen experimental data are derived.Comment: 4 pages, 4 figures, Proc. of the 30th International Cosmic Ray
Conference, July 3 - 11, 2007, Merida, Yucatan, Mexico (ICRC07
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