Still, have some questions in my mind:
It has been found that right-handed neutrinos can be very good dark matter candidates as they are stable, super heavy (200 billion times heavier than the heaviest known particle) and super-weakly interact.
You mean (sorry they propose) that the 20% of universe's mass is composed of those right-handed neutrinos?
But this sounds a little bit strange to me. Because as you mentioned they are not observed yet. And maybe impossible to detect. Which makes them only theoretical particles such as axions or WIMPs. And by the way, Has this theory any explanation about dark energy as well? (I've taken a quick look at the paper you've linked, however, I need to read it at a later time in detail)
- I've found the stupidity by myself when I read the post again. And had a disappointment while I was about to click that link to learn about 'right-handed neutrinos' and saw the hyperlink leads me to another place :))
Yes, this is exactly what the model predicts.
They are by no means axions or wimps because they just don't interact at all with the Standard Model. They are not thermal relics but dark matter is here produced via another mechanism connected to gravity.
PS: sorry for the disappointment. There is a second link a couple of sentences later in the post :)