There are so many options for dark matter that is is really likely that we didn't find it yet. For now, a lot of options are excluded, but many still remains un-probed. The paper I discuss actually propose a method to cover more of this "dark matter model space" if we can call it that way.

I'm thinking; if dark matter is discovered, would the name still be dark matter, or would it change to white matter? :D

No, it will stay dark. The dark qualifier comes from the fact that dark matter does not interact electromagnetically (that is a fact, it just can't do it). Since electromagnetism is mediated by photons (or light), here comes the name.

Is it clearer?