Abstract
There are several cosmological constraints for finding candidates, coming from galaxies, clusters, but also constraints from quantum physics, fermions or bosons. Particle physics points to a wide variety of candidates : weakly interacting WIMPS from super-symmetry (SUZY), whose most stable particle is the neutralino ; sterile neutrinos, which could have a mass of the order of a few keV ; primordial black holes ; axions, or axion-like particles, with masses of the order of 10**(-21) eV. Only upper limits are obtained in direct or indirect detection experiments. Another possibility is that of modified gravity.
