Examining the cancellation mechanism of neutron EDM in a model with dilaton-dominated susy breaking

TL;DR

This paper investigates how the neutron's electric dipole moment can be suppressed through cancellations in a dilaton-dominated SUSY breaking model, revealing specific parameter space conditions for small EDM and CP violation.

Contribution

It identifies the parameter space regions where accidental cancellations occur and constrains the phases of SUSY parameters to achieve small neutron EDM.

Findings

Cancellations occur at specific points in parameter space.

Phase of μ must be small (~0.1) for most of the parameter space.

Possible to generate ε of order 10^{-6} within the model.

Abstract

We examine the cancellation mechanism between the different contributions to the electric dipole moment of the neutron in a model with dilaton-dominated SUSY breaking. We find these accidental cancellations occur at few points in parameter space. For a wide region of this space we must constrain the phase of $\mu$ to be of order $10^{-1}$ and have the phases of $A$ and $\mu$ strongly correlated in order to have small neutron EDM. Moreover, we consider the indirect CP violation parameter $\epsilon$ in this region where the electric dipole moment is less than the experimental limit and find that we can generate $\epsilon$ of order $10^{-6}$.