Hello Jay, and welcome to PF, where you posted in the homework area. This doesn't look like homework at all (If I am wrong, correct me and use the template provided under the "new thread" button).
Your question is difficult to answer at a suitable level, because I don't know what that level should be.
Basically, all kinds of things can happen if particles "meet". Especially if they "meet" with a lot of violence, as in head-to-head collisions at speeds close to the speed of light. In such collisions, high energy physicists study what are conserved quantities. Total energy (using E = mc
2) and momentum are only a few. A lot of others fall under the common denominator "quantum numbers".
Point is that with enough energy, you can make almost anything -- in partice - antiparticle pairs. They can exchange constituents, or decay into other (lighter) stuff, etc.
Surf around in
partice physics a little bit and welcome to this wonderful world!