Towards a 3+4 minimal model

I have a framework now: standard model, plus four right-handed neutrinos, plus a new scalar for inflation.

The four new neutrinos are there to provide dark matter on four scales: keV for the "warm dark matter" that may be the bulk of it, O(10) GeV for the CDMS signal (Dan Hooper also argues that there are galactic-center emissions consistent with a 10 GeV particle), O(100) GeV for the Fermi line, O(300) GeV for the PAMELA/AMS positron excess.

At this point I have little idea how well this will fare. I am especially unsure of whether GeV-mass sterile neutrinos are suitable for producing any of the DM signals; but there's lots more to worry about too. The point is just that it's a place to start, a framework to test. It can be replaced with something more complex if it just can't work.

Expect progress in developing this framework to be slow-to-nonexistent.