Pardon my layman ignorance. When the particles pop in and out of existence, how does mass manage to remain the same? Or does mass keep changing and is not fixed quantity but rather a range?
And what do come out of, and where do they go?
Gluons pop up out of nothing to carry this energy that struggling bound quarks have and add up into nothing passing their energy back to quarks.
If you pump in even more energy into this system (for example by smashing something into it) even something like new quark-antiquark pair can pop up into existence and one of the original quarks might fly off away with one of the new particles to form a separate meson. The other particle from the created pair stays and changes the identity of three quark particle so it's no longer a neutron but some other three quark particle.
The energy that is present withing the system of bound components must be something else.