The WIMP of a Minimal Technicolor Theory

We consider the possibility that a massive fourth family neutrino, predicted by a recently proposed minimal technicolor theory, could be the source of the dark matter in the universe. The model has two techniflavors in the adjoint representation of an SU(2) techicolor gauge group and its consistency requires the existence of a fourth family of leptons. By a suitable hypercharge assignement the techniquarks together with the new leptons look like a conventional fourth standard model family. We show that the new (Majorana) neutrino N can be the dark matter particle if $m_N \sim 100-500$ GeV and the expansion rate of the Universe at early times is dominated by an energy component scaling as $\rho_\phi \sim a^{-6}$ (kination), with $\rho_\phi/\rho_{\rm rad} \sim 10^{-6}$ during the nucleosynthesis era.