Effective Action and Soft Supersymmetry Breaking for Intersecting D-brane Models

TL;DR

This paper analyzes supersymmetry breaking in intersecting D-brane models within type II string theories, deriving soft terms and discussing phenomenological implications like gauge unification and flavor physics.

Contribution

It provides a general framework for calculating soft supersymmetry breaking terms in intersecting D-brane models without specifying the breaking mechanism.

Findings

Gauge coupling unification is limited to specific moduli space regions.

Flavor changing neutral currents can be sufficiently suppressed.

Brief discussion on CP violation, electric dipole moments, and dark matter.

Abstract

We consider a generic scenario of spontaneous breaking of supersymmetry in the hidden sector within N=1 supersymmetric orientifold compactifications of type II string theories with D-branes that support semi-realistic chiral gauge theories. The soft breaking terms in the visible sector of the models are computed in a standard way without specifying the breaking mechanism, which leads to expressions that generalize those formerly known for heterotic or type I string models. The elements of the effective tree level supergravity action relevant for this, such as the Kahler metric for the matter fields, the superpotential of the visible sector and the gauge kinetic functions, are specified by dimensional reduction and duality arguments. As phenomenological applications we argue that gauge coupling unification can only occur in special regions of the moduli space; we show that flavor changing neutral currents can be suppressed sufficiently for a wide range of parameters, and we briefly address the issues of CP violation, electric dipole moments and dark matter, as well.