Unifying CP violations of quark and lepton sectors

Understand

A preliminary determination of the Dirac phase in the PMNS matrix is $\dell\approx -\frac{\pi}{2}$.

• A rather accurately determined Jarlskog invariant $J$ in the CKM matrix is close to the maximum.
• Since the phases in the CKM and PMNS matrices will be accurately determined in the future, it is an interesting problem to relate these two phases.
• This can be achieved in a families-unified grand unification if the weak CP violation is introduced spontaneously {\it \`a la} Froggatt and Nielsen at a high energy scale, where only one meaningful Dirac CP phase appears.