  We compute the massless spectra of some four dimensional, N=1 supersymmetric
compactifications of the type I string. The backgrounds are non-toroidal
Calabi-Yau manifolds described at special points in moduli space by Gepner
models. Surprisingly, the abstract conformal field theory computation reveals
Chan-Paton gauge groups as big as SO(12) x SO(20) or SO(8)^4 x SO(4)^3.

High Energy Physics - Theory