Sakharov conditions: how matter came to dominate the universe
Andrei Sakharov (1967) identified three necessary conditions for baryogenesis — the dynamical generation of the observed baryon asymmetry η = (n_B − n_B̄)/s ≈ 8.7×10⁻¹¹: (1) Baryon number violation (B-violation), (2) C and CP symmetry violation, (3) Departure from thermal equilibrium. Without all three, any initial baryon excess would be washed out. The electroweak sphaleron process violates B+L, and electroweak baryogenesis via a first-order phase transition is one candidate mechanism.