7 research outputs found
Cosmic Ray Signatures from Decaying Gravitino Dark Matter
We study the charged cosmic rays arising from the slow decay of gravitino
dark matter within supersymmetric scenarios with trilinear R-parity violation.
It is shown that operators of the LLE type can very well account for the recent
anomalies in cosmic ray electron and positron data reported by PAMELA, ATIC and
Fermi LAT, without violating any other bounds. This scenario will soon be
tested by the Fermi LAT data on diffuse gamma ray emission.Comment: To appear in the proceedings of EPS-HEP 2009, Krakow, Polan
Long lived charginos in Natural SUSY?
Supersymmetric models with a small neutralino-chargino mass difference, and
as a result metastable charginos, have been a popular topic of investigation in
collider phenomenology, e.g. in anomaly-mediated models of supersymmetry
breaking. Recently, the absence of any supersymmetric signal at the 8 TeV LHC
data has led to significant interest in the so-called Natural SUSY models with
light higgsinos. These models also have a naturally small neutralino-chargino
mass difference. However, we show here that when relevant indirect constraints
from results at the LHC and elsewhere are applied, this possibility is heavily
constrained within the Minimal Supersymmetric Standard Model (MSSM): massive
metastable higgsinos are not a signature of Natural SUSY.Comment: Extended discussion, updated references, matches version to appear in
JHE
Dark Matter Candidates: A Ten-Point Test
An extraordinarily rich zoo of non-baryonic Dark Matter candidates has been
proposed over the last three decades. Here we present a 10-point test that a
new particle has to pass, in order to be considered a viable DM candidate: I.)
Does it match the appropriate relic density? II.) Is it {\it cold}? III.) Is it
neutral? IV.) Is it consistent with BBN? V.) Does it leave stellar evolution
unchanged? VI.) Is it compatible with constraints on self-interactions? VII.)
Is it consistent with {\it direct} DM searches? VIII.) Is it compatible with
gamma-ray constraints? IX.) Is it compatible with other astrophysical bounds?
X.) Can it be probed experimentally?Comment: 29 pages, 12 figure
Radiative gravitino decays from R-parity violation
We study radiative gravitino decay within the framework of R-violating supersymmetry. For trilinear R-violating couplings that involve the third generation of fermions, or for light gravitinos, we find that the radiative loop-decay dominates over the tree-level ones for a wide set of parameters. We calculate the gravitino decay width and study its implications for cosmology and collider physics. Slow-decaying gravitinos are good dark matter candidates, for a range of parameters that would also predict observable R-violating signatures in colliders. In general the branching ratios are very dependent on the relative hierarchies of R-violating operators, and may provide relevant information on the flavour structure of the underlying fundamental theory
Gamma-Rays from Decaying Dark Matter.
We study the prospects for detecting gamma-rays from decaying Dark Matter
(DM), focusing in particular on gravitino DM in R-parity breaking vacua. Given
the substantially different angular distribution of the predicted gamma-ray
signal with respect to the case of annihilating DM, and the relatively poor (of
order 0.1) angular resolution of gamma-ray detectors, the best strategy
for detection is in this case to look for an exotic contribution to the
gamma-ray flux at high galactic latitudes, where the decaying DM contribution
would resemble an astrophysical extra-galactic component, similar to the one
inferred by EGRET observations. Upcoming experiments such as GLAST and AMS-02
may identify this exotic contribution and discriminate it from astrophysical
sources, or place significant constraints on the mass and lifetime of DM
particles.Comment: 15 pages, 5 figures, LaTeX with iopart.cls. Minor changes, typos
corrected and references added/updated. Version accepted for publication in
JCA