MORE ON THE CLASSIFICATION OF 3 GENERATION SUPERSTRING MODELS

Compactification of the ten dimensional heterotic E8×E8 string theory on the Calabi-Yau manifold due to Tian and Yau yields three chiral families of quarks and leptons. The interesting four dimensional gauge groups, after symmetry breaking of E6 through Wilson loops, turn out to be SU(3)c×SU(3)L×SU(3)R and SU(6)×U(1). The classification of all possible models according to their discrete symmetries for the case of standard embedding of (SU(3))3 in E6 had recently been presented. The present paper completes this analysis by presenting the classification of models for the second inequivalent embedding of (SU(3))3 in E6 and for the two inequivalent embeddings of SU(6)×U(1) in E6. Only the flipped version of SU(6) is realized for the latter models. © 1980.