Large CP Phases and the Cancellation Mechanism in EDMs in SUSY, String and Brane Models

Abstract

We show that EDMs obey a simple approximate scaling under the transformation $m_0\to λm_0,m_{1/2}\to λm_{1/2}$ in the large $μ$ region when $μ$ itself obeys the same scaling, ie., $μ\to λμ$. In the scaling region the knowledge of a single point in the MSSM parameter space where the cancellation in the EDMs occur allows one to generate a trajectory in the $m_0-m_{1/2}$ plane where the cancellation mechanism holds and the EDMs are small. We illustrate these results for MSSM with radiative electro-weak symmetry breaking constraints. We also discuss a class of D brane models based on Type IIB superstring compactifications which have non-universal phases in the gaugino mass sector and allow large CP violating phases consistent with the EDM constraints through the cancellation mechanism. The scaling in these D brane models and in a heterotic string model is also discussed.