Oscillations and CP violation in meson systems

Abstract

Abstract This chapter covers the diverse physical effects that have been measured in meson systems over the past half-century, including the surprising discovery of CP violation and its subsequent study. Flavour oscillations and regeneration are described for the kaon system, which is used to formulate the mathematical description of the combined mixing and decay of the meson states. The observation of neutral meson mixing, which has now been achieved in all four of the known neutral meson systems, is described using box diagrams. The chapter then extensively discusses the phenomenon of CP violation, how it was discovered, the conditions under which it manifests itself in experimentally accessible situations, and how the Kobayashi–Maskawa formalism incorporates it into the standard model. The different origins of CP violation are considered, including mixing and direct CP violation. CP violation studies from LHCb and B-factories are reviewed. CP violation is related to the unitarity triangle.