How does baryon asymmetry explain why the universe is composed of more matter than anti-matter?
Baryons, such as protons and neutrons, are composite particles comprised of three valence quarks, with a “sea” of virtual quarks, anti-quarks, and gluons popping into and out of existence on an extremely short time-scale. Anti-baryons, such as anti-protons and anti-neutrons, are the same, only their valence particles are three anti-quarks. The baryonic number of a baryon is 1, and that of an anti-baryon is -1. The baryonic number of a quantum state is conserved in most interactions. However, to have the abundance of baryons relative to anti-baryons observed in the universe, given the theoretical equality between the two at the time of the Big Bang, CP symmetry must be broken. The minimal standard model includes such symmetry breaking in the electro-weak interaction. However, as stated in http://www.physics.mcgill.ca/~guymoore/research/baryogenesis.html the rate is too small to explain the asymmetry between baryons and anti-baryons. There are several models proposed to explain this, but
