16 research outputs found
Spectral Gamma-ray Signatures of Cosmological Dark Matter Annihilation
We propose a new signature for weakly interacting massive particle (WIMP)
dark matter, a spectral feature in the diffuse extragalactic gamma-ray
radiation. This feature, a sudden drop of the gamma-ray intensity at an energy
corresponding to the WIMP mass, comes from the asymmetric distortion of the
line due to WIMP annihilation into two gamma-rays caused by the cosmological
redshift. Unlike other proposed searches for a line signal, this method is not
very sensitive to the exact dark matter density distribution in halos and
subhalos. The only requirement is that the mass distribution of substructure on
small scales follows approximately the Press-Schechter law, and that smaller
halos are on the average denser than large halos, which is a generic outcome of
N-body simulations of Cold Dark Matter, and which has observational support.
The upcoming Gamma-ray Large Area Space Telescope (GLAST) will be eminently
suited to search for these spectral features. For numerical examples, we use
rates computed for supersymmetric particle dark matter, where a detectable
signal is possible.Comment: 4 pages, 1 figure. Matches the published version. Conclusions
unchange
The positron excess and supersymmetric dark matter
Using a new instrument, the HEAT collaboration has confirmed the excess of
cosmic ray positrons that they first detected in 1994. We explore the
possibility that this excess is due to the annihilation of neutralino dark
matter in the galactic halo. We confirm that neutralino annihilation can
produce enough positrons to make up the measured excess only if there is an
additional enhancement to the signal. We quantify the `boost factor' that is
required in the signal for various models in the Minimal Supersymmetric
Standard Model parameter space, and find that a boost factor >30 provides good
fits to the HEAT data. Such an enhancement in the signal could arise if we live
in a clumpy halo.Comment: 6 pages, LaTeX, proceedings of the 4th International Workshop on
Identification of Dark Matter (idm2002), York, England, 2-6 September, 200
A new population of WIMPs in the solar system and indirect detection rates
A new Solar System population of Weakly Interacting Massive Particle (WIMP)
dark matter has been proposed to exist. We investigate the implications of this
population on indirect signals in neutrino telescopes (due to WIMP
annihilations in the Earth) for the case when the WIMP is the lightest
neutralino of the MSSM, the minimal supersymmetric extension of the standard
model. The velocity distribution and capture rate of this new population is
evaluated and the flux of neutrino-induced muons from the center of the Earth
in neutrino telescopes is calculated. We show that the effects of the new
population can be crucial for masses around 60-120 GeV, where enhancements of
the predicted muon flux from the center of the Earth by up to a factor of 100
compared to previously published estimates occur. As a result of the new WIMP
population, neutrino telescopes should be able to probe a much larger region of
parameter space in this mass range.Comment: 6 pages, 4 figures. Contribution to the proceedings of the 3rd
International Workshop on the Identification of Dark Matter (IDM2000) in
York, in pres
DarkSUSY - A numerical package for dark matter calculations in the MSSM
The question of the nature of the dark matter in the Universe remains one of
the most outstanding unsolved problems in basic science. One of the best
motivated particle physics candidates is the lightest supersymmetric particle,
assumed to be the lightest neutralino. We here describe DarkSUSY, an advanced
numerical FORTRAN package for supersymmetric dark matter calculations which we
release for public use. With the help of this package, the masses and
compositions of various supersymmetric particles can be computed, for given
input parameters of the minimal supersymmetric extension of the Standard Model
(MSSM). For the lightest neutralino, the relic density is computed, using
accurate methods which include the effects of resonances, pair production
thresholds and coannihilations. Accelerator bounds are checked to identify
viable dark matter candidates. Finally, detection rates are computed for a
variety of detection methods, such as direct detection and indirect detection
through antiprotons, gamma-rays and positrons from the Galactic halo or
neutrinos from the center of the Earth or the Sun.Comment: 6 pages, no figures. Contribution to the proceedings of the 3rd
International Workshop on the Identification of Dark Matter (IDM2000) in
York, in pres