Perspectives on the detection of supersymmetric Dark Matter

Up to now searches for Dark Matter (DM) detection have not been successful, either because our paradigm in how DM signals should look like are wrong or the detector sensitivity is still too low in spite of the large progress made in recent years. We discuss both possibilities starting with what we know about DM from cosmology and why Supersymmetry provides such an interesting paradigm for cosmology and particle physics in order to appreciate what it means to give up this paradigm. In addition, we compare the predicted cross sections for direct and indirect DM detection with observations with emphasis on the latest developments. Especially, we discuss the possible origins of the two hotly debated candidates for a DM annihilation signal, namely the positron excess and the Fermi GeV excess, which are unfortunately incompatible with each other and more mundane astrophysical explanations exist.Comment: 18 pages, 12 figures. Invited talk at ICNFP2017, August 2017, Crete, Greec

Determination of the Local Dark Matter Density in our Galaxy

The rotation curve, the total mass and the gravitational potential of the Galaxy are sensitive measurements of the dark matter halo profile. In this publication cuspy and cored DM halo profiles are analysed with respect to recent astronomical constraints in order to constrain the shape of the Galactic DM halo and the local DM density. All Galactic density components (luminous matter and DM) are parametrized. Then the total density distribution is constrained by astronomical observations: 1) the total mass of the Galaxy, 2) the total matter density at the position of the Sun, 3) the surface density of the visible matter, 4) the surface density of the total matter in the vicinity of the Sun, 5) the rotation speed of the Sun and 6) the shape of the velocity distribution within and above the Galactic disc. The mass model of the Galaxy is mainly constrained by the local matter density (Oort limit), the rotation speed of the Sun and the total mass of the Galaxy from tracer stars in the halo. It is shown from a statistical chi^2 fit to all data that the local DM density is strongly positively (negatively) correlated with the scale length of the DM halo (baryonic disc). Since these scale lengths are poorly constrained the local DM density can vary from 0.2 to 0.4 GeV/cm^3 (0.005 - 0.01 M_sun/pc^3) for a spherical DM halo profile and allowing total Galaxy masses up to 2 * 10^12 M_sun. For oblate DM halos and dark matter discs, as predicted in recent N-body simulations, the local DM density can be increased significantly.Comment: 10 pages, 8 figure

Becoming more systematic about flexible learning: beyond time and distance

Changes in higher education frequently involve the need for more flexibility in course design and delivery. Flexibility is a concept that can be operationalized in many ways. One approach to conceptualizing flexibility within courses is to distinguish planning-type flexibility, which the instructor can designate before the course begins and which needs to be managed when the course is offered, for interpersonal flexibility, which relates more to the dynamics of the course as it is experienced by the learners. Course management systems (CMSs) offer options that can support both of these sorts of flexibility, if instructors use the CMSs with a systematic frame of reference. The instructor faces challenges in managing both types of flexibility, but the experience at one institution shows that being systematic about flexibility choices and ways to support those choices in the institutional CMS can help in meeting these challenges

Simulation of beam induced lattice defects of diamond detectors using FLUKA

Diamond is more and more used as detector material for particle detection. One argument for diamond is its higher radiation hardness compared to silicon. Since various particles have different potential for radiation damage at different energies a scaling rule is necessary for the prediction of radiation damage. For silicon detectors the non-ionising energy loss (NIEL) is used for scaling the effects of different particles. A different way of predicting the radiation damage is based on the Norget-Robinson-Torrens theorem to predict the number of displacements per atom (DPA). This provides a better scaling rule since recombination effects are taken into account. This model is implemented in the FLUKA Monte Carlo simulations package for protons, neutrons and pions. We compare simulation results of NIEL and DPA for diamond and silicon material exposed to protons, neutrons and pions for a wide range of energies

The dark connection between the EGRET excess of diffuse Galactic gamma rays, the Canis Major dwarf, the Monoceros ring, the INTEGRAL 511 keV annihilation line, the gas flaring and the Galactic rotation curve

The EGRET excess of diffuse Galactic gamma rays shows all the key features of dark matter annihilation (DMA) for a WIMP mass in the range 50-100 GeV, especially the distribution of the excess is compatible with a standard halo profile with some additional ringlike substructures at 4 and 13 kpc from the Galactic centre. These substructures coincide with the gravitational potential well expected from the ring of dust at 4 kpc and the tidal stream of dark matter from the Canis Major satellite galaxy at 13 kpc, as deduced from N-body simulations fitting to the Monoceros ring of stars. Strong independent support for this substructure is given by the gas flaring in our Galaxy. The gamma rays from DMA are originating predominantly from the hadronization of mono-energetic quarks, which should produce also a small, but known fraction of protons and antiprotons. Bergstrom et al. an antiproton flux far above the observed antiproton flux and they conclude that the DMA interpretation of the EGRET excess can therefore be excluded. However, they used an isotropic propagation model, i.e. the same diffusive propagation in the disk and the halo. It is shown that an anisotropic propagation model is consistent with the EGRET gamma ray excess, the antiproton flux and the ratios of secondary/primary and unstable/stable cosmic ray particles. Such an anisotropic propagation is supported by the large bulge/disk ratio of the positron annihilation line, as observed by the INTEGRAL satellite. In this case no need for new sources specific to the bulge are needed, so the claimed evidence for strong DMA in the bulge from these observations is strongly propagation model dependent.Comment: 22 pages, 7 figures, Invited talk at DARK2007, Sydney, Sept. 200