5 research outputs found
Decaying Hidden Dark Matter in Warped Compactification
The recent PAMELA and ATIC/Fermi/HESS experiments have observed an excess of
electrons and positrons, but not anti-protons, in the high energy cosmic rays.
To explain this result, we construct a decaying hidden dark matter model in
string theory compactification that incorporates the following two ingredients,
the hidden dark matter scenario in warped compactification and the
phenomenological proposal of hidden light particles that decay to the Standard
Model. In this model, on higher dimensional warped branes, various warped
Kaluza-Klein particles and the zero-mode of gauge field play roles of the
hidden dark matter or mediators to the Standard Model.Comment: 15 pages; v4, several clarifications added, update on Fermi/HESS
result
Astrophysical Uncertainties in the Cosmic Ray Electron and Positron Spectrum From Annihilating Dark Matter
In recent years, a number of experiments have been conducted with the goal of
studying cosmic rays at GeV to TeV energies. This is a particularly interesting
regime from the perspective of indirect dark matter detection. To draw reliable
conclusions regarding dark matter from cosmic ray measurements, however, it is
important to first understand the propagation of cosmic rays through the
magnetic and radiation fields of the Milky Way. In this paper, we constrain the
characteristics of the cosmic ray propagation model through comparison with
observational inputs, including recent data from the CREAM experiment, and use
these constraints to estimate the corresponding uncertainties in the spectrum
of cosmic ray electrons and positrons from dark matter particles annihilating
in the halo of the Milky Way.Comment: 21 pages, 9 figure
Dark matter and collider phenomenology of split-UED
We explicitly show that split-universal extra dimension (split-UED), a
recently suggested extension of universal extra dimension (UED) model, can
nicely explain recent anomalies in cosmic-ray positrons and electrons observed
by PAMELA and ATIC/PPB-BETS. Kaluza-Klein (KK) dark matters mainly annihilate
into leptons because the hadronic branching fraction is highly suppressed by
large KK quark masses and the antiproton flux agrees very well with the
observation where no excess is found . The flux of cosmic gamma-rays from pion
decay is also highly suppressed and hardly detected in low energy region (E<20
GeV). Collider signatures of colored KK particles at the LHC, especially q_1
q_1 production, are studied in detail. Due to the large split in masses of KK
quarks and other particles, hard p_T jets and missing E_T are generated, which
make it possible to suppress the standard model background and discover the
signals.Comment: 32 pages, 15 figure