The String CP Problem

Abstract

We show that string models with low energy supersymmetry which accommodate the fermion mass hierarchy generally give non-universal soft trilinear couplings (A-terms). In conjunction with the apparently large Cabibbo-Kobayashi-Maskawa (CKM) phase, this results in large fermion EDMs even in the absence of CP violating phases in the supersymmetry breaking terms and the mu-term. Nonobservation of the EDMs therefore implies that strings select special flavor and/or supersymmetry breaking patterns.