Why does matter become antimatter?

Question

i understand that in a particle accelorator, mass is propeled at speeds close to 'c', then when 2 atoms collide, 1 atom and 1 anti atom is created, but y dos dat occur????

Answer 1

You got that wrong.

Two atoms colliding with each other does not create 1 atom and 1 anti-atom. It does not work that way. Besides, they don't collide atoms in a particle accelerator. They either collide protons or neutrons. None of these would result in the creation of matter and anti matter. The collision would  result into either of three possibilities. The particles will destroy each other in a burst of particle fragments ,or would remain as the same particles with different direction of velocities, or would assimilate each other and turn into a mini-black hole.

Matter and anti- matter are created in pairs simultaneously. This is explained by Dirac's Hole Theory and verified by the Anderson Pair Production Experiment.

Dirac's theory says that " When sufficient energy is imparted to matter in the negative state, it transcends unknown barriers and come to existence in the positive state leaving a void in the negative state.

In the Anderson experiment, a gamma ray of 2 million electron volts (2MEV) was focused to an aluminum foil and two particles were simultaneously created; an electron and a positron which is the anti-matter counterpart of the electron. This process is called Pair Production.

Answer 2

It's not that simple.  Start with the reference.  They're just beginning to find ways to make enough cold antiprotons to study.