It is the process by which gamma rays of sufficiently high energy, for example 1.02 MeV (i.e. \(2 \: m_ec^2\)) and above will produce a pair of a particle and it's antiparticle (in this example, an electron-positron pair). Any excess energy that cannot be converted into a particle pair will manifest as the kinetic energy of the particles.

Pair Production always produces particle-antiparticle pairs to conserve the quantum states, but scientists are confused why there is more matter than antimatter in the observable universe.

Processes that can change matter-antimatter balance of the universe do exist, even in standard model (look under instantons and sphalerons), but at low energies are extremely rare. Also black holes seem to destroy information about the types of particles thrown into them, thus formation and subsequent evaporation of a black hole appears to change the matter-antimatter balance of the universe.

How does pair production work

Quantum Field Theory doesn't explain it very well, but here is what I could obtain:

https://physics.stackexchange.com/questions/274322/how-does-gamma-gamma-pair-production-really-work

It's hard to describe anything beyond a certain "resolution", if you get the idea.

Mass is bound energy

Four protons combine to form alpha particles, and in this process, some mass deficit is lost as photons.
But three quarks combine to form protons, and in this case, there is excess bound energy in the form of gluons.

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