Related papers: GUT's with Adjoint Higgs from Superstrings
We investigate grand unified theories (GUTs) in scenarios where electroweak (EW) symmetry breaking is triggered by a light composite Higgs, arising as a Nambu-Goldstone boson from a strongly interacting sector. The evolution of the standard…
The first part of this talk presents the general complexion of baryon and lepton number non-conservation that may arise in the context of quark-lepton unification. The second part presents the status of grand unification with and without…
We propose a novel way to break grand unified gauge symmetries via the Hosotani mechanism in models that can accommodate chiral fermions. Adjoint scalar fields are realized through the so-called diagonal embedding method which is often used…
Finite Unified Theories (FUTs) are N = 1 supersymmetric Grand Unified Theories (GUTs) which can be made finite to all-loop orders, based on the principle of reduction of couplings, and therefore are provided with a large predictive power.…
We show that models of the Dirac gaugino can naturally be embedded into a kind of the grand unified theory (GUT), the grand gauge-Higgs unification (gGHU) model, with the gauge group SU(5)\times SU(5)/Z_2 on an S^1/Z_2 orbifold. The…
A simple extension of the minimal renormalizable supersymmetric SO(10) grand unified theory by adding a 120-dimensional Higgs representation is examined. This brings new antisymmetric contributions to the relevant quark and lepton mass sum…
We study the bosonic structure of $F$-term Nambu-Goto cosmic strings forming in a realistic SO(10) implementation, assuming standard hybrid inflation. We describe the supersymmetric grand unified theory, and its spontaneous symmetry…
Grand unified models in four dimensions typically suffer from the doublet-triplet splitting problem. This obstacle can be overcome in higher-dimensional settings, where a non-trivial gauge group topography can explain the simultaneous…
After an introduction to the Higgs sector of supersymmetric extensions of the Standard Model, recent results on radiative corrections to Higgs boson masses and couplings are reviewed. The phenomenology of supersymmetric Higgs searches at…
We reconsider the minimal SU(5) Grand Unified Theory (GUT) in the context of no-scale supergravity, assuming that the soft supersymmetry-breaking parameters satisfy universality conditions at some input scale M_in above the GUT scale M_GUT.…
A recent analysis of the methods by which higher-level gauge symmetries are realized in string theory has made it possible to systematically obtain new constraints on string GUT model-building. In this paper, we perform such a study for the…
String Unified Models based on the $k=1$ level of the Kac-Moody Algebra, predict the existence of ``exotic'' new states which carry fractional electric charges. We analyse the possibility of considering these ``exotics'' as preonic matter…
Higher dimensional grand unified theories, with gauge symmetry breaking by orbifold compactification, possess SU(5) breaking at fixed points, and do not automatically lead to tree-level gauge coupling unification. A new framework is…
Boundary conditions on an extra-dimensional interval can be chosen to break bulk gauge symmetries and to reduce the rank of the gauge group. We consider this mechanism in models with gauge trinification. We determine the boundary conditions…
We consider the coupling of axions to gauge bosons in higher-dimensional Grand Unified Theories (GUT) inspired by string theory constructions with D-branes on orbifold singularities, the so-called orbifold GUTs. Due to their topological…
The conventional supersymmetric grand unified theories suffer from two serious problems, the large mass splitting between doublet and triplet Higgs multiplets, and the too long lifetime of the proton. A unification model based on a…
We introduce a new approach for studying unified supergravity models. In this approach all the parameters of the grand unified theory (GUT) are fixed by imposing the corresponding number of low energy observables. This determines the…
We study the realistic structure of F-term Nambu-Goto cosmic strings forming in a general supersymmetric Grand Unified Theory implementation, assuming standard hybrid inflation. Examining the symmetry breaking of the unification gauge group…
From the string partition function, we discuss the mass-shell and GSO projection conditions valid for Kaluza-Klein (KK) as well as massless states in the heterotic string theory compactified on a nonprime orbifold. Based on the obtained…
The interpretation of the apparent unification of gauge couplings within supersymmetric theories depends on uncertainties induced through heavy particle thresholds. While in standard grand unified theories these effects can be estimated…