Supersymmetry Breaking and Moduli Stabilization with Anomalous U(1) Gauge Symmetry

We discuss spontaneous supersymmetry (SUSY) breaking in a model with an anomalous $U(1)_A$ symmetry. In this model, the size of the each term in the superpotential is controlled by the $U(1)_A$ charge assignment and SUSY is spontaneously broken via the Fayet-Iliopoulos of $U(1)_A$ at the meta-stable vacuum. In the global SUSY analysis, the gaugino masses become much smaller than the sfermion masses, because an approximate R-symmetry appears at the SUSY breaking vacuum. In thi...

In the context of the field theory limit of superstrings, we consider an almost realistic model of supersymmetry breaking by gaugino condensation which includes, through nonperturbative corrections to the K\"ahler potential, dilaton stabilization at a value compatible with a weak coupling regime. Invariance under modular transformations is ensured through a Green-Schwarz term and string threshold corrections, which lead to moduli stabilization at the self-dual point. We are t...

We study the effective field theory of KKLT and LVS moduli stabilisation scenarios coupled to an anti-D3-brane at the tip of a warped throat. We describe the presence of the anti-brane in terms of a nilpotent goldstino superfield in a supersymmetric effective field theory. The introduction of this superfield produces a term that can lead to a de Sitter minimum. We fix the Kaehler moduli dependence of the nilpotent field couplings by matching this term with the anti-D3-brane u...

A generic lesson of string theory is that the coupling constants of an effective low energy theory are determined by the vacuum values of a set of fields - the so-called moduli - some of which are stabilized at relatively low masses by non-perturbative effects. We argue that the physics of these moduli cannot be separated from the issues of dynamical and gauge mediated supersymmetry breaking. To illustrate this point we present a modified version of the type IIB KKLT model wh...

We consider the phenomenological consequences of fixing compactification moduli. In the simplest KKLT constructions, stabilization of internal dimensions is rather soft: weak scale masses for moduli are generated, and are of order m_\sigma ~ m_{3/2}. As a consequence one obtains a pattern of soft supersymmetry breaking masses found in gravity and/or anomaly mediated supersymmetry breaking (AMSB) models. These models may lead to destabilization of internal dimensions in the ea...

We use the F-term dynamical supersymmetry breaking models with metastable vacua in order to uplift the vacuum energy in the KKLT moduli stabilization scenario. The main advantage compared to earlier proposals is the manifest supersymmetric treatment and the natural coexistence of a TeV gravitino mass with a zero cosmological constant. We argue that it is generically difficult to avoid anti de-Sitter supersymmetric minima, however the tunneling rate from the metastable vacuum ...

We point out that an anomalous gauge U(1) symmetry is a natural candidate for being the mediator and messenger of supersymmetry breaking. It facilitates dynamical supersymmetry breaking even in the flat limit. Soft masses are induced by both gravity and the U(1) gauge interactions giving an unusual mass hierarchy in the sparticle spectrum which suppresses flavor violations. This scenario does not suffer from the Polonyi problem.

In an attempt to implement gauge mediation in string theory, we study string effective supergravity models of supersymmetry breaking, containing anomalous gauge factors. We discuss subtleties related to gauge invariance and the stabilization of the Green-Schwarz moduli, which set non-trivial constraints on the transmission of supersymmetry breaking to MSSM via gauge interactions. Given those constraints, it is difficult to obtain the dominance of gauge mediation over gravity ...

We propose a general scenario for moduli stabilization where low-energy supersymmetry can be accommodated with a high scale of inflation. The key ingredient is that the stabilization of the modulus field during and after inflation is not associated with a single, common scale, but relies on two different mechanisms. We illustrate this general scenario in a simple example, where during inflation the modulus is stabilized with a large mass by a Kahler potential coupling to the ...

We derive general expressions for soft terms in supergravity where D-terms contribute significantly to the supersymmetry breaking in addition to the standard F-type breaking terms. Such D-terms can strongly influence the scalar mass squared terms, while having limited impact on gaugino masses and the B-terms. We present parameterisations for the soft terms when D-terms dominate over F-terms or become comparable with them. Novel patterns emerge which can be tested phenomenolog...