YUKAWA TEXTURES AND ANOMALIES

We augment the Minimal Supersymmetric Standard Model with a gauged fam ily-dependent U(1) to reproduce Yukawa textures compatible with experi ment, In the simplest model with one extra chiral electroweak singlet field, acceptable textures require this U(1) to be anomalous. The canc ellation of its anomalies by a generic Green-Schwarz mechanism require s sin(2) theta(w) = 3/8 at the string scale, suggesting a superstring origin for the standard model.