Possible Duplicate: How do we know Dark Matter isn't simply Neutrinos? If there are primardian neutrinos and since they have some mass however low, could neutrinos form the dark matter ...
May be not neutrinos, but antineutrinos? Or both types? In the last case, why they didn't annihilate and what is the ratio of relic neutrinos to relic antineutrinos? Is that ratio somehow related to ...