Related papers: Extracting predictions from Supergravity/Superstri…
Within the context of supergravity-coupled supersymmetry, fields which are gauge and global singlets are usually considered anathema. Their vacuum expectation values are shifted by quadratically divergent tadpole diagrams which are cutoff…
We consider the predictions for the hierarchy of mass scales, the fine structure constant, the radii of compactification and the soft SUSY breaking terms which follow if SUSY breaking is triggered by a gaugino condensate.
In this thesis we discuss non-perturbative phenomena emerging in gauge and in string/supergravity theories. We compute the partition function of 5D minimal supersymmetric U(1) gauge theory with extra adjoint matter in general…
Most discussions of supersymmetric grand unified theories assume universality of the soft supersymmetry breaking terms at the grand scale. We point out that the behaviour of these theories might change significantly in the presence of…
We examine the problem of supersymmetry breaking in realistic superstring standard--like models which are constructed in the free fermionic formulation. We impose a supersymmetric vacuum at the Planck scale by requiring vanishing F and D…
Perturbative superstring theory is revisited, with the goal of giving a simpler and more direct demonstration that multi-loop amplitudes are gauge-invariant (apart from known anomalies), satisfy space-time supersymmetry when expected, and…
We study some conditions for the hierarchy $m_{3/2} << M_P$ to occur naturally in a generic effective supergravity theory. Absence of fine-tuning and perturbative calculability require that the effective potential has a sliding gravitino…
We explain the need for a theory of quantum gravity and some general ideas about string theory, including the idea of the derivation of the Hawking Bekenstein entropy formula for extremal black holes. We then give a general description of…
The region of moduli space of string theories which is most likely to describe the "real world" is where the string coupling is about unity and the volume of extra compact dimensions is about the same size as the string volume. Here we map…
The first part of this review tries to provide a self-contained view of supersymmetry breaking from the bottom-up perspective. We thus describe N=1 supersymmetry in four dimensions, the Standard Model and the MSSM, with emphasis on the…
We discuss a supersymmetric extension of the standard model with an extra U(1) gauge symmetry. In this model, the proton stability is guaranteed by the gauge symmetry without invoking R parity. The gauge symmetry breakdown automatically…
We review the development of understanding for the problem of ultraviolet divergences in supergravity. This history proceeds from initial constructions of counterterms invariant under the relevant degrees of local supersymmetry, through a…
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…
We consider the role of supersymmetry breaking soft terms that are present in generalized Narain compactifications of heterotic string theory, in which local supersymmetry is spontaneously broken, with gravitino masses being inversely…
The search for a theory of quantum gravity faces two great challenges: the incredibly small scales of the Planck length and time, and the possibility that the observed constants of nature are in part the result of random processes. A…
We discuss the motivations and implications of models of low-energy supersymmetry. We present the case for the minimal supersymmetric standard model, which we define to include the minimal particle content and soft supersymmetry-breaking…
String theories with (N,N') local world-sheet supersymmetries are related to each other by marginal deformations. This connects N=1 and N=0 theories in which the target-spaces are interpreted as space-times, N=2 theories in which the target…
We present a through discussion of motivations for and phenomenological issues in supersymmetric models with minimal matter content and non-holomorphic soft-breaking terms. Using the unification of the gauge couplings and assuming SUSY is…
String theory is the leading candidate for a unified theory of the standard model and gravity. In the last few years theorists have realized that there is a unique structure underlying string theory. In this unification a prominent role is…
In these lectures we start with a pedagogical introduction of the properties of open and closed superstrings and then, using the open/closed string duality, we construct the boundary state that provides the description of the maximally…