Partial quark-lepton universality and neutrino CP violation

We study a model with partial quark-lepton universality that can naturally arise in grand unified theories. We find that constraints on the model can be reduced to a single condition on the Dirac CP phase $\delta$ in the neutrino sector. Using our current knowledge of the CKM and PMNS mixing matrices, we predict $-32.4^\circ < \delta < 32.0^\circ$ at $2\sigma$.