Forget WIMPs, Axions And MACHOs: Could WIMPzillas Solve The Dark Matter Problem?
“But what, exactly, is dark matter? And, moreover, can we be certain it exists? There are a huge suite of detectors and experiments out there searching for it, and yet no robust, verified, direct detection has ever been reported. There is no smoking gun we can point to and say, “this was an event caused by an interaction with dark matter.” The overwhelming majority of detectors out there are looking for WIMP-type dark matter, with a small contingent also looking for axions. (MACHOs, or other sources of “normal” dark matter, have been ruled out.) But all of this may be misguided. Dark matter might not be any of those things we’re looking for. In fact, it’s arguable that the candidate with the best motivations for it have no experiments to their name at all: WIMPzillas!”
Many detractors of dark matter point to the fact that we haven’t directly detected it yet as evidence that dark matter doesn’t exist. Yet practically every dark matter search that’s ever been performed has focused on just one particular class of dark matter: WIMPs. Well, WIMPs have been constrained very tightly, and we’re no closer to seeing WIMP dark matter than we were decades ago. But in that same time span, we’ve seen a number of exciting discoveries, including neutrino masses, come to fruition. Related to neutrino masses is the idea that there would be super-heavy right-handed neutrino counterparts to the light ones we see today. Could these “WIMPzillas” be the dark matter we’ve been looking for?