I apologize for the very simple question, but I find often the simplest questions are the ones not answered in books. If a free-floating proton collides with a free-floating neutron, do they get bound together by the strong nuclear force? Let's say it's a low-energy collision - both particles are gently meandering the cosmos when they meet. Does the strong force bind them together as soon as they touch forming deuterium? I was wondering if all simple particles like neutrons and proton carry the strong force within them. If the 2 particles meeting does not create a bond, how do they normally bond?