Related papers: Anomalous U(1), gaugino condensation and supergrav…
In string compactification preserving N=1 SUSY, moduli fields are plausible candidates for the messenger of SUSY breaking at low energy scales. In a scenario that moduli-mediated SUSY breaking is significant, the pattern of soft SUSY…
The connection between Supergravity and the low-energy world is analyzed. In particular, the soft Supersymmetry-breaking terms arising in Supergravity, the $\mu$ problem and various solutions proposed to solve it are reviewed. The soft…
We consider the sparticle spectra that arise when anomaly mediation is the source of supersymmetry-breaking and the tachyonic slepton problem is solved by a Fayet-Iliopoulos D-term. We also show how this can lead to a minimal viable…
Grand unified theories (GUTs) can lead to non-universal gaugino masses at the unification scale. We study the implications of such non-universal gaugino masses for the composition of the lightest neutralino in supersymmetric (SUSY) theories…
We introduce an $N=1$ supergravity model based on the gauged shift symmetry of a single chiral multiplet, which can be identified with the string dilaton or a compactification modulus. The model allows for a tunably small and positive value…
It is well known that D-brane instantons can generate contributions to the effective superpotential of gauge theories living on D-branes which are perturbatively forbidden by global U(1) symmetries. We extend this idea to theories with…
A consistent theory of supersymmetry breaking must have a hidden sector, an observable sector, and must be embedded in a locally supersymmetric theory which arises from string theory. For phenomenological reasons it must also transmit…
In four dimensional superstring models, the gauge group normally contains extra U(1)s that are broken at a high energy scale. We show that the presence of the extra U(1)s is crucial for the phenomenological viability of string scenarios,…
The requirement of Yukawa coupling unification highly constrains the SUSY parameter space. In several SUSY breaking scenarios it is hard to reconcile Yukawa coupling unification with experimental constraints from B(b->s gamma) and the muon…
We investigate, at the microscopic level, the compatibility between D-term potentials from world-volume fluxes on D7-branes and non-perturbative superpotentials arising from gaugino condensation on a different stack of D7-branes. This is…
The phenomenological consequences of the dilaton-type soft supersymmetry breaking terms in the context of the next to minimal supersymmetric standard model are investigated. We always find a very low top quark mass. As a consequence such…
A brief review of non-universalities in the soft SUSY breaking sector of supergravity grand unification is given. The effects of these non-universalities on the analysis of event rates in neutralino nucleus scattering are discussed. An…
We find a new class of metastable de Sitter solutions in compactifications of six-dimensional supergravity motivated by type IIB or heterotic string vacua. Two Fayet-Iliopoulos terms of a local U(1) symmetry are generated by magnetic flux…
We obtain exact relations (valid to all orders in the coupling constant) for the running gaugino mass in supersymmetric gauge theories, treating the soft supersymmetry breaking effects in the linear approximation. If a supersymmetry…
We revisit the F-term hybrid inflation model in supergravity. In particular, we point out that a constant term in the superpotential has significant effects on the inflaton dynamics. It is shown that the hybrid inflation model suffers from…
Closed string fluxes induce generically SUSY-breaking soft terms on supersymmetric type IIB orientifold compactifications with D3/D7 branes. This was studied in the past by inserting those fluxes on the DBI+CS actions for adjoint D3/D7…
We report the construction of large new classes of models which break supersymmetry dynamically. We then turn to model building. Two of the principal obstacles to constructing simple models of dynamical supersymmetry breaking are the…
We discuss spontaneous supersymmetry breaking in $N=2$ globally supersymmetric theories describing abelian vector multiplets. The most general form of the action admits, in addition to the usual Fayet-Iliopoulos term, a magnetic…
The particle spectrum of the supersymmetric extension of the standard model with a gauge singlet is studied. Soft supersymmetry breaking terms are explicitly chosen to be non-universal according to orbifold string theory. they depend on…
It is well known that the supersymmetric finite threshold effects can induce substantial corrections to the Standard Model fermion masses. This opens an alternative possibility to correct the problematic mass ratios of the lighter…