What if the Masses of the First Two Quark Families are not Generated by the Standard Higgs?

Understand

We point out that, in the context of the SM, $|V^2_{13}| + | V^2_{23}|$ is expected to be large, of order one.

• The fact that $|V^2_{13}| + |V^2_{23}| \approx 1.6 \times 10^{-3}$ motivates the introduction of a symmetry S which leads to $V_{CKM} ={1\>\!\!\!\mathrm{I}} $, with only the third generation of quarks acquiring mass.
• We consider two scenarios for generating the mass of the first two quark generations and full quark mixing.
• One consists of the introduction of a second Higgs doublet which is neutral under S.