Note on Mediation of Supersymmetry Breaking from Closed to Open Strings

TL;DR

This paper investigates how supersymmetry breaking effects are transmitted from closed to open strings in string theory, revealing the absence of anomaly mediation and detailing gaugino mass generation under specific boundary conditions.

Contribution

It extends previous analyses by showing the absence of anomaly mediation in general string vacua and calculates the two-loop gaugino mass when supersymmetry is broken via Scherk-Schwarz boundary conditions.

Findings

No anomaly mediation around perturbative string vacua.

Gaugino mass arises at two loops with a specific dependence on gravitino mass and gauge coupling.

Provides detailed behavior of supersymmetry breaking mediation in string models.

Abstract

We discuss the mediation of supersymmetry breaking from closed to open strings, extending and improving previous analysis of the authors in Nucl. Phys. B 695 (2004) 103 [hep-th/0403293]. In the general case, we find the absence of anomaly mediation around any perturbative string vacuum. When supersymmetry is broken by Scherk-Schwarz boundary conditions along a compactification interval perpendicular to a stack of D-branes, the gaugino acquires a mass at two loops that behaves as $m_{1/2}\sim g^4 m_{3/2}^3$ in string units, where $m_{3/2}$ is the gravitino mass and $g$ is the gauge coupling.