Low-Energy Predictions of Lopsided Family Charges

We consider the Froggatt-Nielsen (FN) mechanism reproducing the observed mass hierarchies and mixing angles for quarks and leptons. The large $\nu_\mu $-$ \nu_\tau$ mixing suggested from recent Superkamiokande experiments on the atmospheric neutrinos implies lopsided FN U(1) charges for the lepton doublets. There are two possible charge assignments to generate the large $\nu_\mu$-$ \nu_\tau$ mixing. We point out that the two models with different charge assignments have distinct low-energy predictions and hence they are distinguishable in future neutrino experiments on such as CP violation and $2\beta 0\nu$ decay.