We study the possibility of identifying dark matter properties from XENON-like 100 kg experiments and the GLAST satellite mission. We show that whereas direct detection experiments will probe efficiently light WIMPs, given a positive detection (at th
e 10% level for $m_{chi} lesssim 50$ GeV), GLAST will be able to confirm and even increase the precision in the case of a NFW profile, for a WIMP-nucleon cross-section $sigma_{chi-p} lesssim 10^{-8}$ pb. We also predict the rate of production of a WIMP in the next generation of colliders (ILC), and compare their sensitivity to the WIMP mass with the XENON and GLAST projects.
In a recent article, M. Tegmark poses the hypothesis that our known universe is a ``baggage free mathematical structure among many other possible ones, which also correspond to other physical universes --Mathematical Universe Hypothesis, MUH. Natural
ly, questions arise, such as how to obtain the physical properties of our world from the mathematical structure, or how many possibilities exist for a Universe minimally similar to ours. In this letter we present some results which can be regarded as a strengthening of MUH, as they give some hints on the derivation of spacetime in current physics from a baggage free mathematical structure. Concretely, we argue that the set of mathematical structures which can be interpreted as a description of a spacetime is drastically reduced, if one admits some natural postulates on minimal symmetry. Furthermore, the apparently very particular form of classical Galilei-Newton and relativistic spacetimes, is not arbitrary and cannot be regarded as ``two possibilities among arbitrarily many others. In fact, such theories are determined by a single mathematical structure which only permits four possible types of spacetimes. Finally, we show how the minimal postulates on symmetry can be endowed with a simple physical interpretation, i.e., they acquire ``baggage in a natural way.
