Towards a Realistic Picture of CP Violation in Heterotic String Models

We find that dilaton dominated supersymmetry breaking and spontaneous CP violation can be achieved in heterotic string models with superpotentials singular at the fixed points of the modular group. A semi-realistic picture of CP violation emerges in such models: the CKM phase appears due to a complex VEV of the T-modulus, while the soft supersymmetric CP phases are absent due to an axionic-type symmetry.