Modular Weights, U(1)'s and Mass Matrices

Abstract

We derive the scalar mass matrices in effective supergravity models augmented by a $U(1{)}_F$ family symmetry. Simple relations between $U(1{)}_F$ charges and modular weights of the superfields are derived and used to express the matrices with a minimum number of parameters. The model predicts a branching ratio for the $\mu \to e\gamma$ process close to the present experimental limits.

Comments: LaTex file, 11 pages, 1 Figure.Typos corrected and a reference has been added. Accepted in Phys. Lett. B