SUPERSYMMETRIC THEORY OF FLAVOR WITH RADIATIVE FERMION MASSES

Supersymmetric theories involving a spontaneously broken flavor symmet ry can lead to fermion masses which vanish at the tree level but are g enerated by radiative corrections. In the context of supersymmetric th eories with minimal low energy field content we discuss which fermion masses and mixings may be obtained radiatively, and find that constrai nts from flavor-changing phenomenology imply that only the first gener ation fermion masses and some (but not all) CKM mixings can naturally come from radiative corrections. We also consider general conditions o n theories of flavor which guarantee the existence of tree-level massl ess fermions while having nontrivial CKM matrix elements at the tree l evel. Two complete models of flavor are presented. In the first model, all first generation fermion masses are radiatively generated. In the second model, the electron and up quark mass are due to radiative cor rections whereas the down mass appears at the tree level, as does a su ccessful prediction for the Cabibbo angle sin theta(c)=root m(d)/m(s).