4 research outputs found
Adiabatic compression and indirect detection of supersymmetric dark matter
Recent developments in the modelling of the dark matter distribution in our
Galaxy point out the necessity to consider some physical processes to satisfy
observational data. In particular, models with adiabatic compression, which
include the effect of the baryonic gas in the halo, increase significantly the
dark matter density in the central region of the Milky Way. On the other hand,
the non-universality in scalar and gaugino sectors of supergravity models can
also increase significantly the neutralino annihilation cross section. We show
that the combination of both effects gives rise to a gamma-ray flux arising
from the Galactic Center largely reachable by future experiments like GLAST. We
also analyse in this framework the EGRET excess data above 1 GeV, as well as
the recent data from CANGAROO and HESS. The analysis has been carried out
imposing the most recent experimental constraints, such as the lower bound on
the Higgs mass, the \bsg branching ratio, and the muon . In addition, the
recently improved upper bound on has also been taken
into account. The astrophysical (WMAP) bounds on the dark matter density have
also been imposed on the theoretical computation of the relic neutralino
density through thermal production.Comment: 32 pages, 11 figures, final version to appear in JCA
Two photon annihilation of Kaluza-Klein dark matter
We investigate the fermionic one-loop cross section for the two photon
annihilation of Kaluza-Klein (KK) dark matter particles in a model of universal
extra dimensions (UED). This process gives a nearly mono-energetic gamma-ray
line with energy equal to the KK dark matter particle mass. We find that the
cross section is large enough that if a continuum signature is detected, the
energy distribution of gamma-rays should end at the particle mass with a peak
that is visible for an energy resolution of the detector at the percent level.
This would give an unmistakable signature of a dark matter origin of the
gamma-rays, and a unique determination of the dark matter particle mass, which
in the case studied should be around 800 GeV. Unlike the situation for
supersymmetric models where the two-gamma peak may or may not be visible
depending on parameters, this feature seems to be quite robust in UED models,
and should be similar in other models where annihilation into fermions is not
helicity suppressed. The observability of the signal still depends on largely
unknown astrophysical parameters related to the structure of the dark matter
halo. If the dark matter near the galactic center is adiabatically contracted
by the central star cluster, or if the dark matter halo has substructure
surviving tidal effects, prospects for detection look promising.Comment: 17 pages, 3 figures; slightly revised versio
Collider, direct and indirect detection of supersymmetric dark matter
We present an overview of supersymmetry searches, both at collider
experiments and via searches for dark matter (DM). We focus on three DM
possibilities in the SUSY context: the thermally produced neutralino, a mixture
of axion and axino, and the gravitino, and compare and contrast signals that
may be expected at colliders, in direct detection (DD) experiments searching of
DM relics left over from the Big Bang, and indirect detection (ID) experiments
designed to detect the products of DM annihilations within the solar interior
or galactic halo. Detection of DM particles using multiple strategies provides
complementary information that may shed light on the new physics associated
with the dark matter sector. In contrast to the mSUGRA model where the measured
cold DM relic density restricts us to special regions mostly on the edge of the
m_0-m_{1/2} plane, the entire parameter plane becomes allowed if the
universality assumption is relaxed in models with just one additional
parameter. Then, thermally produced neutralinos with a well-tempered mix of
wino, bino and higgsino components, or with a mass adjusted so that their
annihilation in the early universe is Higgs-resonance-enhanced, can be the DM.
Well-tempered neutralinos typically yield heightened rates for DD and ID
experiments compared to generic predictions from minimal supergravity. If
instead DM consists of axinos (possibly together with axions) or gravitinos,
then there exists the possibility of detection of quasi-stable next-to-lightest
SUSY particles at colliding beam experiments, with especially striking
consequences if the NLSP is charged, but no DD or ID detection. The exception
for mixed axion/axino DM is that DD of axions may be possible.Comment: 28 pages, 11 eps figures; invited contribution to NJP Focus Issue on
"Dark Matter and Particle Physics