Per google, you have to have a collision because of the law of conservation of momentum otherwise won’t allow for pair production. It’s an open question how we

Per google, you have to have a collision because of the law of conservation of momentum otherwise won’t allow for pair production. It’s an open question how we get a universe of matter out of seemingly only producing mass energy in matter/anti-matter symmetry. Sounds like a sure Nobel prize for that one, too.