Supersymmetry, however, has one rather serious problem

Supersymmetry modifies the quantum vacuum and can explain naturally why the Higgs boson is light, provided that the mass of the superparticles is not too large, i.e. in reach of the LHC. Remarkably, such superparticles could also constitute the dark matter of the universe: many supersymmetric models predict the existence of a massive, electrically neutral and stable superparticle, which provides just the right amount of dark matter! Supersymmetry, however, has one rather serious problem: there is so far no experimental evidence for the existence of superparticles.

via Searching for supersymmetry: some frustration but no despair | Michael Krämer | Life & Physics | Science |