While the PAMELA collaboration has recently confirmed the cosmic ray positron excess, it is interesting to review the effects of dark matter subhalos on the predicted antimatter signals. We recall that, according to the general subhalo properties as inferred from theoretical cosmology, the enhancement cannot be larger than ~20 for the antimatter yield. This bound is obviously different from what is found for γ-rays. We also show some predictions for supersymmetric benchmark models observable at the LHC and derived in the cosmological N-body framework, but remind the existing discrepancy between the profiles derived from N-body experiments and the current observations.

The annihilations of WIMPs can lead to the production of very-high energy (VHE) γ-rays in the final state. These VHE γ-rays may be detected by Imaging Atmospheric Cherenkov Telescopes (IACTs) like the H.E.S.S. instrument. We review here the search for such annihilations towards the Galactic Center and the Canis Major overdensity. Constraints on the velocity-weighted cross-sections ⟨σv⟩ of WIMPs are computed within the framework of supersymmetric and Kaluza-Klein extensions of the Standard Model of Particle Physics.

The PAMELA satellite-borne experiment was launched from the Baikonur launch site on the 15th of June 2006. Since July 2006 it is daily delivering to ground 16 GBytes of data. The instrument is composed by a magnetic spectrometer, a time-of-flight system, a silicon-tungsten electromagnetic calorimeter, a neutron detector and anticoincidence scintillators. The primary scientific goal is to searching for evidence of dark matter particle annihilations studying antiparticles fluxes. Preliminary results concerning antiproton-proton and positron-electron ratios are presented.

ANTARES (Astronomy with a Neutrino Telescope and Abyss environmental RESearch) is the largest neutrino detector currently operating in the Northern hemisphere. The detection principle relies on the observation of Cerenkov light emitted by muons resulting from charged current neutrino interactions in the water surrounding the detector and the seafloor below. The detector, which was completed in May 2008, consists of twelve lines (each housing 75 photomultipliers), placed at a depth of about 2480 meters 40 km off the coast of Toulon, France. The telescope is built to search for astrophysical neutrino point sources and for neutrinos created in self-annihilation of Dark-Matter particles. A likely source of such neutrino emission would be the Sun, where Dark Matter particles are expected to accumulate. Predictions of the neutrino flux originating from the Sun have been made based on the minimal Supergravity (mSugra) model including the effect of neutrino oscillations. Within mSugra the lightest supersymmetric particle, if a neutralino, is a possible candidate for cold Dark Matter. Using the general features of ANTARES in the energy range from 10 GeV to 400 GeV a prediction for exclusion limits for three years of datataking has been calculated.

To detect WIMP (Weakly Interacting Massive Particle)-nucleon scattering events and thus validate the dark matter hypothesis, the CRESST (Cryogenic Rare Event Search with Superconducting Thermometers) and the future EURECA (European Underground Rare Event Calorimeter Array) experiments use modularized cryogenic detectors operated at mK temperatures. We present an attempt to realize so-called composite detectors for this purpose. A detailed thermal detector model to investigate the composite detector design concerning signal evolution and detector performance is described.

CRESST is an experiment for the direct detection of dark matter particles via nuclear recoils. The CRESST detectors, based on CaWO4 scintillating crystals, are able to discriminate γ and β background by simultaneously measuring the light and phonon signals produced by particle interactions. The discrimination of the background is possible because of the different light output (Quenching Factor, QF) for nuclear and electron recoils. In this article a measurement is shown, aimed at the determination of the QFs of the different nuclei (O, Ca, W) of the detector crystal at 40–60 mK using an 11 MeV neutron beam produced at the Maier-Leibnitz-Laboratorium in Garching (MLL).

We propose new measurement system for direct detection of WIMPs with directional information using nano imaging tracker (NIT) and X-ray microscope. The NIT made of fine grains of emulsion has a good spatial resolution of several tens nanometer and the X-ray microscope can work as a readout instrument for sub-micron track structure instead of ordinary optical microscope. Wolter type-I fluorescence X-ray microscope utilizing Ag-L line can be applied to this system. Crucial issues are reduction of background event due to random fog and to develop fast selection method of WIMP event candidates.

The MIMAC project is based on a matrix of Micro Time Projection Chambers (μ-TPC) for Dark Matter search, filled with He3 or CF4 and using ionization and tracks. The first measurement of the energy resolution of this μ-TPC is presented as well as its low threshold.

I consider the relation of explanations for the observed data to testability in the following contexts: observational and experimental detection of dark matter; observational and experimental detection of dark energy or a cosmological constant Λ; observational or experimental testing of the multiverse proposal to explain a small non-zero value of Λ; and observational testing of the possibility of large scale spatial inhomogeneity with zero Λ.