In a nuclear reaction, protons and neutrons are separated from each other. My question is, why can protons and neutrons separate, but quarks can not separate from each other. When the nucleus is intact, the gauge bosons for the strong nuclear force, gluons are responsible for holding quarks within a single proton or neutron together. They are also responsible for holding protons to neutrons. So why do quarks within a particular proton (or neutron for that matter) get separated? Don't they "feel" the tearing force that is the sum of the protons repelling each other? Does it have something to do with "glueballs" (don't laugh, but someone suggested this, hopefully they weren't messing with me) that don't apply between protons and neutrons.