I'm not trying to advance a pet theory here .. it's really just a question. Why don't physicists serious consider the possibilty of energy/mass contained in the false vacuum as the source of Dark Matter? At least I've never heard of a serious one in these terms. Real particles and their anti-particles are said to be created & annihilated constantly. Also virtual particles are supposed to be exchanged all the time. I would think the mass equivalent of the energy needed for these things is significant. Maybe there is some constraint of not feeling the gravitation as these things happen underneath the limits of the HUP?