R adiative Transm ission ofLepton Flavor H ierarchies

W e discussa one loop m odelforneutrino m asseswhich leadsto a seesaw-like form ula with the dierence thatthe charged lepton m assesreplace the unknown Dirac m assm atrix presentin the usualseesaw case.Thisisaconsiderablereduction ofparam etersin theneutrinosectorand predicts a strong hierarchicalpattern in therighthanded neutrino m assm atrix thatiseasily derived from a U(1)H fam ily sym m etry. The m odelisbased on the left-right gauge group with an additional Z4 discrete sym m etry which gives vanishing neutrino Dirac m asses andnite M ajorana m asses arising attheoneloop level.Furtherm ore,itisoneofthefew m odelsthatnaturally allow forlarge (butnotnecessarily m axim al)m ixing anglesin thelepton sector.A generalization ofthem odelto thequark sectorrequiresthreeiso-spin singletvector-like down typequarks,asin E6.Them odel predictsan inertdoublettypescalardark m atter.