Related papers: Supersymmetry breaking, open strings and M-theory
We review physical motivations and possible realizations of string vacua with large internal volume and/or low string scale and discuss the issue of supersymmetry breaking. In particular, we describe the key features of Scherk-Schwarz…
We use type I string models with supersymmetry broken by compactification (\`a la Scherk-Schwarz) in order to test the weak gravity conjecture in the presence of runaway potentials in a perturbative string theory setting. For a finite value…
We analyze the Scherk-Schwarz (SS) supersymmetry breaking in brane-world five dimensional theories compactified on the orbifold $S^1/\mathbb{Z}_2$. The SS breaking parameter is undetermined at the tree-level (no-scale supergravity) and can…
We study spontaneous supersymmetry breaking induced by brane-localized dynamics in five-dimensional supergravity compactified on S^1/Z_2. We consider a model with gravity in the bulk and matter localized on tensionless branes at the…
We present a string theory construction in which the particle physics contributions to the one-loop vacuum energy exactly cancel, whilst the gravitational contributions are suppressed in the size of one or two large extra dimensions. This…
We consider the 3+1 visible sector to live on a Hanany-Witten D-brane construction in type IIA string theory. The messenger sector consists of stretched strings from the visible brane to a hidden D6-brane in the extra spatial dimensions. In…
We present a five-dimensional model compactified on an interval where supersymmetry is broken by the Scherk-Schwarz mechanism. The gauge sector propagates in the bulk, two Higgs hypermultiplets are quasilocalized, and quark and lepton…
We study the transmission of supersymmetry breaking via gravitational interactions in a five-dimensional brane-world compactified on $S^1/Z_2$. We assume that chiral matter and gauge fields are confined at the orbifold fixed points, where…
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…
I review the relations between mass scales in various string theories and in M-theory. I discuss physical motivations and possible consistent realizations of large volume compactifications and low string scale. Large longitudinal…
We analyze in detail supersymmetry breaking by compactification of the fifth dimension in M-theory in the compactification pattern $11d \to 5d \to 4d$ and find that a superpotential is generated for the complex fields coming from $5d$…
Type I string theory in the presence of internal magnetic fields provides a concrete realization of split supersymmetry. To lowest order, gauginos are massless while squarks and sleptons are superheavy. For weak magnetic fields, the correct…
We present a novel mechanism of supersymmetry breaking embeddable in string theory and simultaneously sharing the main advantages of (sequestered) gravity and gauge mediation. It is driven by a Scherk-Schwarz deformation along a compact…
We study Type I string theory compactified on a T^6/Z_3 orientifold. The low-energy dynamics is most conveniently analyzed in terms of D3-branes. We show that a sector of the theory, which corresponds to placing an odd number of D3-branes…
Keeping N=1 supersymmetry in 4-dimension and in the leading order, we disuss the various orbifold compactifications of M-theory suggested by Horava and Witten on $T^6/Z_3$, $T^6/Z_6$, $T^6/Z_{12}$, and the compactification by keeping…
We analyze some features of the role that extra dimensions, of radius $R$ in the TeV$^{-1}$ range, can play in the soft breaking of supersymmetry and the spontaneous breaking of electroweak symmetry. We use a minimal model where the gauge…
We study SU(N) supersymmetric Yang-Mills theory with massless adjoint matter defined on $M^3\otimes S^1$. The SU(N) gauge symmetry is broken maximally to $U(1)^{N-1}$, independent of the number of flavor and the boundary conditions of the…
We develop a formalism for computing one-loop gravitational corrections to the effective action of D-branes. In particular, we study bulk to brane mediation of supersymmetry breaking in models where supersymmetry is broken at the tree-level…
This thesis studies meta- and exactly stable supersymmetry breaking mechanisms in heterotic and type IIB string theories and constructs an F-theory Grand Unified Theory model for neutrino physics in which neutrino mass is determined by the…
We construct D=4 Type I vacua with massless content remarkably close to that of the standard model of particle physics. They are tachyon-free non-supersymmetric models which are obtained starting with a standard D=4, N=1 compact Type IIB…