Related papers: Towards a Realistic F-theory GUT
We present an example of SUSY SU(6) GUT, which predicts an excellent value for $\al_s(M_Z)(\simeq 0.119)$, in comparison with the value $\al_s^0(M_Z)\simeq 0.126$ of minimal SUSY SU(5). A crucial role is played by the vectorlike multiplets…
Dynamical symmetry breaking is studied in an E_6 GUT model of a single generation of fermions with strong 4-fermi interactions. The effective potential is analyzed analytically by the help of Michel's conjecture and the result is confirmed…
We study the generation of the GUT scale through radiative corrections in the context of a R-symmetric "flipped" SU(5) X U(1)_X model. A negative mass squared term for the GUT Higgs fields develops due to radiative effects along a flat…
We present a minimal viable Gauge-Higgs Grand Unification scenario in warped space based on a $SU(6)$ bulk symmetry - unifying the gauge symmetries of the SM and their breaking sector. We show how the issue of light exotic new states is…
Finite Unified Theories (FUTs) are N=1 supersymmetric Grand Unified Theories that can be made all-loop finite, leading to a severe reduction of the free parameters. We review the investigation of FUTs based on SU(5) in the context of…
We consider a minimal non-supersymmetric $SO(10)$ Grand Unified Theory (GUT) model that can reproduce the observed fermionic masses and mixing parameters of the Standard Model. We calculate the scales of spontaneous symmetry breaking from…
We investigate gauge coupling unification for F-theory respectively Type IIB orientifold constructions of SU(5) GUT theories with gauge symmetry breaking via non-trivial hypercharge flux. This flux has the non-trivial effect that it splits…
The semi-simple unification model based on SU(5)_GUT \times U(3)_H gauge group is an interesting extension of the minimal SU(5)_GUT grand unification theory (GUT), since it solves the two serious problems in the standard GUT: the…
We study models in which soft supersymmetry-breaking parameters of the MSSM become universal at some unification scale, $M_{in}$, above the GUT scale, $\mgut$. We assume that the scalar masses and gaugino masses have common values, $m_0$…
Supersymmetric GUTs are the most natural extension of the Standard model unifying electroweak and strong forces. Despite their indubitable virtues, among these the gauge coupling unification and the quantization of the electric charge, one…
We review SO(10) grand unified theories (GUTs) in four and five dimensions (4D and 5D). The renormalizable minimal SO(10) SUSY GUT is the central theme of this review. It is very predictive and makes it possible to construct all mass…
A review is given on the consistency checks of GUT, which unify the electroweak and strong nuclear forces into a single theory. Such theories predict a new kind of force, which could provide answers to several open questions in cosmology.…
We study in detail the structure of Grand Unified Theories derived as the low-energy limit of orbifold four-dimensional strings. To this aim, new techniques for building level-two symmetric orbifold theories are presented. New classes of…
While non-abelian groups are undoubtedly the cornerstone of Grand Unified Theories (GUTs), phenomenology shows that the role of abelian and discrete symmetries is equally important in model building. The latter are the appropriate tool to…
A version of M-theory phenomenology is proposed in which the symmetry is based on the group $SO(10) \times SO(10) \times SO(10) \times U(1) \times U(1)$. Each SO(10) group acts on a single generation. The $U(1) \times U(1)$ is regarded as…
Several dimensionful parameters needed for model building can be engineered in a certain class of SU(5) F-theory GUTs by adding extra singlet fields which are localized along pairwise intersections of D7-branes. The values of these…
We analyse the phenomenology of a model of neutrino masses inspired by $\mathrm{E}_{6}$ GUT unification in which the exotic neutrinos can be present at low scales. The model introduces vector-like isosinglet down-type quarks, vector-like…
We present a supersymmetric (SUSY) model based on trinification $[\mathrm{SU}(3)]^3$ and family $\mathrm{SU}(3)_\mathrm{F}$ symmetries embedded into a maximal subgroup of $\mathrm{E}_8$, where the sectors of light Higgs bosons and leptons…
A systematic approach is followed in order to identify realistic D-brane models at toric del Pezzo singularities. Requiring quark and lepton spectrum and Yukawas from D3 branes and massless hypercharge, we are led to Pati-Salam extensions…
We study the consequences of cancellation of cubic Abelian anomalies in F-theory GUT models that utilise hypercharge flux in the presence of additional U(1) symmetries. We show that a mixed anomaly between the hypercharge and two U(1) gauge…