CPviolation
CP violation is the phenomenon in particle physics where the combined symmetry of charge conjugation (C) and parity (P) is not preserved by certain weak interactions. Charge conjugation swaps particles with antiparticles, while parity inverts spatial coordinates. If CP were exact, the laws governing particles would be identical for matter and antimatter under these transformations. CP violation was first observed in 1964 in the decays of neutral K mesons by Cronin and Fitch, signaling that CP is not exact in nature. Subsequent measurements detected CP violation in B meson systems and other processes, establishing it as a fundamental part of the Standard Model.
In the Standard Model, CP violation arises primarily from a complex phase in the quark mixing matrix,
The strong interaction in quantum chromodynamics could also violate CP via a theta term, but experiments bound
CP violation is one of the Sakharov conditions required to generate the matter–antimatter asymmetry of the