Related papers: Large volume supersymmetry breaking without decomp…
We study the four-dimensional effective theory arising from ten-dimensional heterotic supergravity compactified on manifolds with torsion. In particular, given the heterotic superpotential appropriately corrected at $\mathcal{O}(\alpha')$…
We discuss the spontaneous supersymetry breaking within the low-energy effective supergravity action of four-dimensional superstrings. In particular, we emphasize the non-universality of the soft supersymmetry breaking parameters, the…
We deconstruct the non-supersymmetric SU(5) breaking by discrete symmetry on the space-time $M^4\times S^1$ and $M^4\times S^1/(Z_2\times Z_2')$ in the Higgs mechanism deconstruction scenario. And we explain the subtle point on how to…
We discuss models where N=1 global supersymmetry is spontaneously broken, at the classical level, in the presence of non-anomalous gauge interactions. We take such models as effective theories, valid up to some suitable scale and arising…
We discuss the four-dimensional massless spectrum of supersymmetric Minkowski compactifications of ten-dimensional heterotic supergravity, including the anomaly cancelation condition. This can be calculated from restrictions arising from…
We present an additional test of the recent proposal for describing supersymmetry breaking due to gaugino condensation in the strong coupling regime, by a Scherk-Schwarz mechanism on the eleventh dimension of M-theory. An analysis of…
In this talk I review the issues of supersymmetry breaking and radion stabilization in a five dimensional theory compactified on the Z_2 orbifold. Supersymmetry breaking by Scherk-Schwarz boundary conditions is interpreted as spontaneous…
The Higgs quartic coupling has now been indirectly measured at the electroweak scale. Assuming no new low-scale physics, its running is known and, together with gauge and Yukawa couplings, it is a crucial new piece of information…
In the framework of heterotic compactifications, we consider the one-loop corrections to the gauge couplings, which were shown to be free of any infra-red ambiguity. For a class of N=2 models, namely those that are obtained by toroidal…
Some old and new ideas on symmetry breaking, based on the presence of extra dimensions that have been the subject of a very fast development and intensive studies during the last years, will be presented in these lectures. Special attention…
We consider models with a noncompact symmetry in the framework of $\mathcal{N}=1$ supersymmetry. Contrary to the conventional approach, the noncompact symmetry is realized linearly on all fields without constraints. The models are…
We consider supersymmetric models in 5-dimensional space-time compactified on S**1/Z(2) orbifold where N=2 supersymmetry is explicitly broken down to N=1 by the orbifold projection. We find that the residual N=1 supersymmetry is broken…
We propose a new spontaneous supersymmetry breaking mechanism, in which extra compact dimensions play an important role. To illustrate our mechanism, we study a simple model consisting of two chiral superfields, where one spatial dimension…
Four-dimensional string theories predict in general the existence of light exotic particles with fractional electric charges. Such particles could escape present observations if they are confined by a gauge group of the "hidden" sector into…
We study $D \geq 4$-dimensional half-maximal flux backgrounds using exceptional field theory. We define the relevant generalised structures and also find the integrability conditions which give warped half-maximal $\mathrm{Minkowski}_D$ and…
We show that large string threshold corrections can reconcile the string and MSSM unification scales in fermionic strings. This requires at least three moduli with large VEVs which are different from each other and MSSM states arising in an…
In this thesis we analyze the problem of symmetry breaking in models with extra dimensions compactified on orbifolds. In the first chapter we briefly review the main symmetry breaking mechanisms peculiar of extra dimensions such as the…
The dynamical breaking of gauge symmetry in the supersymmetric quantum electrodynamics in three-dimensional spacetime is studied at two-loop approximation. At this level, the effective superpotential is evaluated in a supersymmetric phase.…
Matter is coupled to three-dimensional gravity such that the topological phase is allowed and the (anti-) de Sitter or Poincar\'e symmetry remains intact. Spontaneous symmetry breaking to the Lorentz group occurs if a scalar field is…
We study supergravity models in four dimensions where the hidden sector is superconformal and strongly-coupled over several decades of energy below the Planck scale, before undergoing spontaneous breakdown of scale invariance and…