ABSTRACT
We have discussed CP symmetry in §6.11. We found that if the only interactions in a model are the gauge interactions of fermions, CP cannot be violated. This puts CP in a special position so far as the standard model is concerned. Parity and charge conjugation are both broken by gauge interactions, as we have commented in Ch. 16, in particular through Ex. 16.9 (p 470). The combined symmetry CP cannot be broken in this manner.
