CP Violation
The Big Bang should have produced equal amounts of matter and antimatter, and there should have been total cancellation of both, resulting in a sea of radiation in the universe with no matter. Since this is not the case, after the Big Bang, physical laws must have acted differently for matter and antimatter. The violation of Charge conjugation and Parity symmetry (CP) is a subtle effect observed in the decays of certain particles revealing Nature’s preference for matter over antimatter.