Toward a unified interpretation of quark and lepton mixing from flavor and CP symmetries

Abstract

We discussed the scenario that a discrete flavor group combined with CP symmetry is broken to $Z_2\times CP$ in both neutrino and charged lepton sectors. All lepton mixing angles and CP violation phases are predicted to depend on two free parameters ${\theta }_l$ and ${\theta }_{\nu }$ varying in the range of $[0,\pi )$. As an example, we comprehensively study the lepton mixing patterns which can be derived from the flavor group $\Delta (6n^2)$ and CP symmetry. Three kinds of phenomenologically viable lepton mixing matrices are obtained up to row and column permutations. We further extend this approach to the quark sector. The precisely measured quark mixing angles and CP invariant can be accommodated for certain values of the free parameters ${\theta }_u$ and ${\theta }_d$. A simultaneous description of quark and lepton flavor mixing structures can be achieved from a common flavor group $\Delta (6n^2)$ and CP, and accordingly the smallest value of the group index $n$ is $n=7$.

Comments: 40 pages, 8 figures