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 νμ–ντ 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 νμ–ντ 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 2β0ν decay.