2,848 research outputs found
Upper bounds on signals due to WIMP self--annihilation: comments on the case of the synchrotron radiation from the galactic center and the WMAP haze
Two recent papers reconsider the possibility that the excess of microwave
emission from a region within of the galactic center (the {\it WMAP
haze}), measured by WMAP, can be due to the synchrotron emission originated by
neutralino self-annihilation; on the basis of this possible occurrence, also
upper bounds on the neutralino self-annihilation cross--section are suggested.
In the present note, we show that in the common case of thermal WIMPs in a
standard cosmological model, when the rescaling of the galactic WIMP density is
duly taken into account for subdominant WIMPs, the upper bound applicable
generically to {\it any} signal due to self-conjugate WIMPs is more stringent
than the ones obtained from analysis of the WMAP haze. We also argue that an
experimental upper bound, which can compete with our generic upper limit, can
rather be derived from measurements of cosmic antiproton fluxes, for some
values of the parameters of the astrophysical propagation model. Finally, we
comment on the possible impact of our generic upper bound on the interpretation
of the WMAP haze in terms of thermal neutralinos in a standard cosmological
scheme.Comment: 3 pages, comments and 1 figure adde
Light Neutralinos and WIMP direct searches
The predictions of our previous analyses about possible low-mass (lower than
50 GeV) relic neutralinos are discussed in the light of the most recent results
from WIMP direct detection experiments. It is proved that these light
neutralinos are quite compatible with the new annual-modulation data of the
DAMA Collaboration; our theoretical predictions are also compared with the
upper bounds of the CDMS and EDELWEISS Collaborations.Comment: 4 pages, 1 figures, typeset with ReVTeX4. The paper may also be found
at http://www.to.infn.it/~fornengo/papers/note.ps.gz or through
http://www.to.infn.it/astropart/index.htm
Possible implications of the channeling effect in NaI(Tl) crystals
The channeling effect of low energy ions along the crystallographic axes and
planes of NaI(Tl) crystals is discussed in the framework of corollary
investigations on WIMP Dark Matter candidates. In fact, the modeling of this
existing effect implies a more complex evaluation of the luminosity yield for
low energy recoiling Na and I ions. In the present paper related
phenomenological arguments are developed and possible implications are
discussed at some extent.Comment: 16 pages, 10 figures, preprint ROM2F/2007/15, submitted for
publicatio
Implications for relic neutralinos of the theoretical uncertainties in the neutralino-nucleon cross-section
We discuss the effect induced on the neutralino-nucleon cross-section by the
present uncertainties in the values of the quark masses and of the quark scalar
densities in the nucleon. We examine the implications of this aspect on the
determination of the neutralino cosmological properties, as derived from
measurements of WIMP direct detection. We show that, within current theoretical
uncertainties, the DAMA annual modulation data are compatible with a neutralino
as a major dark matter component, to an extent which is even larger than the
one previously derived. We also comment on implications of the mentioned
uncertainties for experiments of indirect dark matter detection.Comment: 23 pages, 7 figures, 1 table, typeset with ReVTeX. Due to size
limitations, the version on the archive has low resolution figures. A full
version of the paper can be found at
http://www.to.infn.it/~fornengo/papers/dama_sets.ps.g
Embedding the 125 GeV Higgs boson measured at the LHC in an effective MSSM: possible implications for neutralino dark matter
We analyze the phenomenological consequences of assuming that the 125 GeV
boson measured at the LHC coincides with one of the two CP-even Higgs bosons of
an effective Minimal Supersymmetric extension of the Standard Model at the
electroweak scale. We consider the two ensuing scenarios and discuss critically
the role of the various experimental data (mainly obtained at colliders and at
B-factories) which provide actual or potential constraints to supersymmetric
properties. Within these scenarios, properties of neutralinos as dark matter
particles are analyzed from the point of view of their cosmological abundance
and rates for direct and indirect detections.Comment: 14 pages, 14 figures, typeset with ReVTeX4. A version of the paper
with full resolution figures can be found at
http://www.to.infn.it/~scopel/embedding.pd
Towards an Iterative Algorithm for the Optimal Boundary Coverage of a 3D Environment
This paper presents a new optimal algorithm for locating a set of sensors in 3D able to see the boundaries of a polyhedral environment. Our approach is iterative and is based on a lower bound on the sensors' number and on a restriction of the original problem requiring each face to be observed in its entirety by at least one sensor. The lower bound allows evaluating the quality of the solution obtained at each step, and halting the algorithm if the solution is satisfactory. The algorithm asymptotically converges to the optimal solution of the unrestricted problem if the faces are subdivided into smaller part
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