Conveners: Christophe Clément and Klas Hultqvist

Apart from directly detecting the interaction of the dark matter particles (WIMPs) passing through matter on Earth, a possible method to obtain information is to look for the secondary particles produced in their annihilation. These can be gamma rays, detectable by Fermi/GLAST, cosmic ray anti-particles, searched for by PAMELA, or neutrinos searched for in IceCube, emitted from mass concentrations such as the centre of the Earth, the Sun, or the Milky Way. Dark matter particles may also be produced in the proton-proton collisions at LHC, which would make it possible to study their properties more directly. This is particularly true in the appealing case that the WIMPs are supersymmetric particles. The DarkSUSY code is one of the leading tools for analyzing supersymmetric parameter space and compute dark matter properties. The OKC will thus be in an excellent position to design, carry out, and interpret searches for the dark matter particles.

If SUSY particles exist with masses of the order of a few hundred GeV they will be copiously produced already at the low luminosities foreseen for the first years of LHC operation. In this case, a host of new particles, with properties closely tied to those of the dark matter, may be discovered and studied with ATLAS. The emphasis of the ATLAS group at SU is on the search for supersymmetric particles, concentrated along two lines, focusing on relatively inclusive signatures, with a view to optimize the potential for an early discovery. These analyses will be sensitive not only to supersymmetric particles but also to phenomena from a large group of possible extensions of the Standard Model.

The search for gamma-rays from dark matter annihilation in the galactic halo will, now that Fermi/GLAST has come into operation in 2008, have a potential of discovery that is more than two orders of magnitude greater than its predecessor, EGRET, because of larger area, better energy and angular resolutions and larger energy range. Current theoretical results obtained from N-body simulations indicate that the halo will be very clumpy, with dark matter annihilating at a much higher rate than previously thought, which additionally improves the detection possibilities.

To dramatically enhance the detection possibility of dark matter in IceCube, a new denser detector array, Deep Core, positioned at depth inside IceCube and sensitive to lower energies, has been funded by the Wallenberg Foundation, and this gives a whole new branch of physics and astrophysics capability where the OKC plays a leading role. Another alternative being explored is the possibility, present in some specific supersymmetric models, that exotic particles like supersymmetric leptons produced by interactions of high-energy neutrinos, can be detected in IceCube.

The resources of the OKC make it possible to extend and adapt DarkSUSY and related codes to the analysis frameworks of the experimenters, particularly that of ATLAS. If the ATLAS results indicate phenomena beyond the Standard Model, the next step is to characterize these in terms of a theoretically sound model, while in the less attractive scenario in which there are no early experimental discoveries, detailed understanding of phenomenological constraints and assumptions, and of the detector properties, will be needed in order to optimize the searches. Knowledge about the WIMP mass and couplings from ATLAS would make it possible to optimize the IceCube search for WIMP annihilations better, and information on mass-spectra or couplings from other sources would enable more optimized measurements at the ATLAS detector. An optimal effort in this area would require the expertise of a particle physics phenomenologist, and the hiring of such a specialist is given high priority.

Although supersymmetry is a very attractive possibility, it is by no means guaranteed. Until SUSY has been unequivocally established, and the Dark Matter particles identified as supersymmetric, existing and emerging alternative scenarios should be explored theoretically, and experimental results concerning WIMP annihilation rates should be presented also in such contexts. To accomplish this, we will consider a new hiring in order to identify models and questions which should be addressed experimentally, and to strengthen the data interpretation efforts in the experimental groups. Many of the modules in DarkSUSY are in principle usable also for alternative scenarios, but adapting them will also require human resources.

If a particle matching the requirements for Dark Matter is discovered at the LHC, or if a signal is found by direct or indirect detection, predictions will be worked out for signals in the different experiments performed by OKC (as well as others of interest), and also at an upgraded LHC, the SLHC, and the planned International Linear Collider. The rates for indirect detection will depend on details of how dark matter is structured on small scales in the Galaxy. A joint team will be formed with astronomers to determine properties of the smallest dwarf satellite galaxies to make a realistic model of the small-scale structure dark matter halo. This may involve one of our new postdocs with experience from N-body simulations. From this, predictions for gamma-ray, antimatter and neutrino detection can be made. Thus, this task will involve all the groups in OKC.

In short-term, several important steps will be taken: The DarkSUSY software will be organized and harmonized with that used in ATLAS, so that experimental limits, and hopefully findings of new particles can be simultaneously treated by the two. This will require one new person (junior researcher or postdoc) with the appropriate background. The work will involve both the ATLAS and the CoPS group. One year after the start-up in 2009, ATLAS is expected to have collected at least one inverse femtobarn of data, which could be enough to give first indications of new physics if the mass-scale is close to present limits. After the second year of data taking one can expect the order of ten inverse femtobarns, which would allow discovery of SUSY particles up to masses of several hundred GeV.

The analysis of GLAST data will also constrain dark matter annihilation in the galactic halo by 2009, or lead to the discovery of this process. The expansion and continued data taking by IceCube/AMANDA will enhance the sensitivity to annihilations in the Sun and by 2011, with Deep Core, it will be a factor 10 beyond present limits on SUSY WIMPs from direct detection.