Related papers: Supersymmetry breaking and weakly vs. strongly cou…
We study the phenomenological implications of effective supergravities based on string vacua with spontaneously broken N=1 supersymmetry by dilaton and moduli $F$-terms. We further require Minimal String Unification, namely that large…
We provide a simple example of dilaton stabilization in the framework of heterotic string theory. It requires a gaugino condensate and an up-lifting sector similar to the one postulated in type IIB string theory. Its signature is a hybrid…
String theory, if it describes nature, is probably strongly coupled. As a result, one might despair of making any statements about the theory. In the framework of a set of clearly spelled out assumptions, we show that this is not…
We consider twisted moduli contributions to supersymmetry breaking in effective type I string constructions involving intersecting D5_i and D9-branes using Goldstino angles to parametrise the supersymmetry breaking. It is well known that…
Motivated from unified models with string origin, we analyse the constraints from duality invariance on effective supergravity models with an intermediate gauge symmetry. Requiring vanishing vacuum energy and invariance of the…
The on-shell regularization of the one-loop divergences of supergravity theories is generalized to include a dilaton of the type occurring in effective field theories derived from superstring theory, and the superfield structure of the…
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…
In string theory the coupling parameters are functions of moduli fields. The actual values of the coupling constants are then dynamically determined through the vacuum expextation values of these fields. We review the attempts to connect…
We study properties of moduli stabilization in the four dimensional N = 1 supergravity theory with heavy moduli and would-be saxion-axion multiplets including light string-theoretic axions. We give general formulation for the scenario that…
We discuss dilaton and Moduli dominant SUSY breaking scenarios in M-theory. In addition, for the nonperturbative superpotential from gaugino condensation, we discuss the soft terms in the simplest model (only S and T moduli fields) and in…
We explore the possibility of gauge mediation in a paradigm whereby supersymmetry is posited to be an accidental symmetry of Nature and the Standard Model fields are composite bound states that emerge from a conformal field theory. The…
Generically, string models with $N=1$ supersymmetry are not expected to have moduli beyond perturbation theory; stringy non-perturbative effects as well as low energy field-theoretic phenomena such as gluino condensation will lift any flat…
Strongly coupled heterotic $E_8\times E_8$ string theory, compactified to four dimensions on a large Calabi-Yau manifold ${\bf X}$, may represent a viable candidate for the description of low-energy particle phenomenology. In this regime,…
The dilaton field in string theories (if exists) is expected to have a mass of the order of the gravitino mass $m_{3/2}$ which is in a range of $10^{-2}$keV--1GeV in gauge-mediated supersymmetry breaking models. If it is the case, the…
The relation between the Hubble constant and the scale of supersymmetry breaking is investigated in models of inflation dominated by a string modulus. Usually in this kind of models the gravitino mass is of the same order of magnitude as…
In the low energy limit of for M-theory on S^1/Z_2, we calculate the gaugino condensate potential in four dimensions using the background solutions due to Horava. We show that this potential is free of delta-function singularities and has…
We go beyond parameterizations of soft terms in superstring models and investigate the dynamical assumptions that lead to the relative strength of the dilaton {\it vs} the moduli contributions in the soft breaking. Specifically, we discuss…
We study the structure of the soft SUSY-breaking terms obtained from some classes of 4-D strings under the assumption of dilaton/moduli dominance in the process of SUSY-breaking. We generalize previous analysis in several ways and in…
We investigate the low energy properties of string vacua with spontaneously broken $N=1$ supersymmetry by a dilaton $F$-term. As a consequence of the universal couplings of the dilaton, the supersymmetric mass spectrum is determined in…
We show that the dilaton and T-moduli can be stabilized by a single gaugino condensation mechanism in the four-dimensional effective field theory derived from Type IIB orientifolds. A crucial role is played by the mixing of the blowing-up…