Quark Flavor and CP
Quark flavor physics asks which masses, mixing angles, and CP-violating combinations remain meaningful after changing field basis. This chapter connects Yukawa matrices to weak effective Hamiltonians and meson observables, then separates weak CP violation from the strong-CP parameter.
Enter this chapter
Section titled “Enter this chapter”Begin with Flavor Symmetry and Yukawa Spurions to identify flavor breaking through the Yukawa matrices.
Topics
Section titled “Topics”- Flavor Symmetry and Yukawa Spurions — Treats Yukawa couplings as symmetry-breaking tensors.
- Quark Mixing and the CKM Matrix — Extracts charged-current mixing from mass diagonalization.
- Weak Effective Hamiltonians and Flavor-Changing Processes — Combines short-distance coefficients with hadronic matrix elements.
- Neutral-Meson Mixing and Mixing-Induced CP Violation — Evolves a decaying meson–antimeson system.
- Quark CP Violation and the Unitarity Triangle — Builds rephasing-invariant tests of weak CP violation.
- Strong CP and the Axion Interface — Combines the QCD angle with quark-mass phases.
How the ideas fit together
Section titled “How the ideas fit together”A CKM phase contributes to an observable only through combinations unchanged by allowed field rephasings. Weak decay amplitudes also combine Wilson coefficients with renormalized hadronic matrix elements, whose scale and scheme dependences must compensate. Neutral-meson CP violation adds interference between mixing and decay, so a phase assigned to either part alone is insufficient. These facts connect basis invariance to the practical construction of predictions and explain why a fitted coefficient or a phase convention is not itself a measured decay asymmetry. Nir 2005, §§ 2–4.
Where to go next
Section titled “Where to go next”Continue to Neutrino and Lepton Physics to distinguish lepton-number-preserving and lepton-number-violating masses.