Thanks for your response.
AYK there are times when SPV mining or Selfish mning happens & some pools/miners mine empty blocks only sending block reward to their address. In such situations they don't reveal their mind blocks making a secret chain until creating a longer chain thus dropping other candidate chains after a while.

I was wondering if there is a way to watch every candidate chain being created to see which chains & which blocks were mined through a selfish style. I know its hard to address this kind of attack using current protocol state, but may be there is a way to find some solution by watching/logging & analyzing pools/miners behaviors in the past.