11,271 research outputs found
On the offset of the DM cusp and the interpretation of the 130 GeV line as a DM signal
We show that the cusp in the dark matter (DM) distribution required to
explain the recently found excess in the gamma-ray spectrum at energies ~130
GeV in terms of the DM annihilations cannot survive the tidal forces if it is
offset by ~1.5^\circ from the Galactic centre as suggested by observations.Comment: 3 pages, replaced with journal versio
On sgoldstino interpretation of HyperCP events
We discuss possible sgoldstino interpretation of the observation, reported by
HyperCP collaboration, of three decay events with
dimuon invariant mass 214.3 MeV within detector resolution. We find that this
interpretation is consistent in models with (i) parity conservation in
sgoldstino interactions, (ii) pseudoscalar sgoldstino of mass 214 MeV and
heavier scalar sgoldstino, and (iii) low supersymmetry breaking scale, \sqrt{F}
= 2.5-60 TeV. In these models, sgoldstino can be observed in decays
, and at the branching
ratios of at least of order 10^{-12}, 10^{-8} and 10^{-11}, respectively.
The model can be probed also at e^+e^- colliders in the channels
and , where the cross section is likely
to be in the range 1 pb - 5 ab.Comment: 14 pages, 1 figure; v2: replaced with journal version, predictions
for kaons refine
Scale-invariance as the origin of dark radiation?
Recent cosmological data favour R^2-inflation and some amount of non-standard
dark radiation in the Universe. We show that a framework of high energy scale
invariance can explain these data. The spontaneous breaking of this symmetry
provides gravity with the Planck mass and particle physics with the electroweak
scale. We found that the corresponding massless Nambu--Goldstone bosons --
dilatons -- are produced at reheating by the inflaton decay right at the amount
needed to explain primordial abundances of light chemical elements and
anisotropy of the cosmic microwave background. Then we extended the discussion
on the interplay with Higgs-inflation and on general class of inflationary
models where dilatons are allowed and may form the dark radiation. As a result
we put a lower limit on the reheating temperature in a general scale invariant
model of inflation.Comment: 15 pages, 4 figures; v2: replaced with revised version recently
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