If antimatter-dominated regions of space existed, the gamma rays produced in annihilation reactions along the boundary between matter and antimatter regions would be detectable. ... The presence of the resulting antimatter is detectable by the two gamma rays produced every time positrons annihilate with nearby matter.

How antiparticles are created?

Particle and antiparticle pairs are created by large accumulations of energy. ... Conversely, when a particle meets an antiparticle, they annihilate into an intense blast of energy. At the time of the big bang, the high energy density of the universe must have created equal amounts of particles and antiparticles.

Can we find antimatter on Earth?

The antimatter is missing – not from CERN, but from the Universe! At least that is what we can deduce so far from careful examination of the evidence. For each basic particle of matter, there exists an antiparticle with the same mass, but the opposite electric charge.