What is the Principle that gives particles their own actual size?

[cdux]

I was thinking about the relation Star -> White Darf -> Neutron Star -> Quark Star -> Black Hole and I wondered why aren't Black Holes studied as a final stage of that sequence since in Literature a Quark Star is often described as a "Single Hadron".

But then it striked me. Let's assume we do have single hadron, what would make it "shrink" into a Black Hole? And can it even shrink or is it "ready" due to its particle-wave quality a point? For all intends and purposes, could Black Holes be just a single hadron?

 

[questionpost]

could Black Holes be just a single hadron?

Nope, the gravity is too strong.