Related papers: Split Multiplets, Coupling Unification and Extra D…
Motivated by the simplicity and direct phenomenological applicability of field-theoretic orbifold constructions in the context of grand unification, we set out to survey the immensely rich group-theoretical possibilities open to this type…
We investigate a 5D SU(6) grand gauge-Higgs unification model compactified on an orbifold S^1/Z_2. Ordinary quarks and leptons, together with right-handed neutrinos, are just accommodated into a minimal set of representations of the gauge…
We study the 6-dimensional N=2 supersymmetric grand unified theories with gauge group SU(N) and $ SO(M)$ on the extra space orbifolds $T^2/(Z_2)^3$ and $T^2/(Z_2)^4$, which can be broken down to the 4-dimensional N=1 supersymmetric…
We consider supersymmetric non-Abelian gauge theories coupled to hyper multiplets on five and six dimensional orbifolds, S^1/Z_2 and T^2/Z_N, respectively. We compute the bulk and local fixed point renormalizations of the gauge couplings.…
We consider Grand Unified Theories based on $SO(10)$ which originate from $M$ theory on $G_2$ manifolds. In this framework we are naturally led to a novel solution of the doublet-triplet splitting problem involving an extra $\overline{{\bf…
In this article, we review gauge-Higgs unification models based on gauge theories defined on six-dimensional spacetime with $S^2/Z_2$ topology in the extra spatial dimensions. On the extra $S^2/Z_2$ space, non-trivial boundary conditions…
We investigate the high-energy behavior of the scattering amplitudes in the extra dimensional gauge theory where the gauge symmetry is broken by the boundary condition. We study, in particular, the 5-dimensional SU(5) grand unified theory…
We consider the renormalisation group flow of gauge couplings within the so-called exceptional supersymmetric standard model (E$_6$SSM) based on the low energy matter content of 27 dimensional representations of the gauge group $E_6$,…
The geometry of (2,1) supersymmetric sigma-models with isometry symmetries is discussed. The gauging of such symmetries in superspace is then studied. We find that the coupling to the (2,1) Yang-Mills supermultiplet can be achieved provided…
All the possible three-family ${\cal N}=1$ supersymmetric Pati-Salam models constructed with intersecting D6-branes from Type IIA orientifolds on $T^6/(\mathbb{Z}_2\times \mathbb{Z}_2)$ are recently presented in arXiv: 2112.09632. Taking…
The significant heavy threshold effect is found in the supersymmetric SU(5) model with two adjoint scalars, one of which is interpreted as a massive string mode decoupled from the lower-energy particle spectra. This threshold related with…
We analyse the phenomenological implications of a particular class of supersymmetric models with additional space-time dimensions below the unification scale. Assuming the unification of the gauge couplings and using a two-loop calculation…
We study gauge symmetry breaking patterns of the five-dimensional $SU(5)$ grand gauge-Higgs unification compactified on an orbifold $S^1/{\mathbb Z}_2$ with the Hosotani mechanism in the framework of the diagonal embedding method. We find…
We make a detailed analysis of gauge coupling unification in supersymmetry. When the Standard Model gauge group is embedded in a Grand Unified Theory, new particles often appear below the GUT scale in order to predict the right…
We study a novel six-dimensional gauge theory compactified on the $T^2/{\mathbb Z}_3$ orbifold utilizing the diagonal embedding method. The bulk gauge group is $G\times G\times G$, and the diagonal part $G^{\rm diag}$ remains manifest in…
We discuss the anomalous U(1) gauge symmetry as a mechanism of generating the grand-unification scale. We conclude that unification to a simple group cannot be realized unless some parameters are ``tuned'', and that models with product…
The apparent unification of gauge couplings around 10^16 GeV is one of the strong arguments in favor of Supersymmetric extensions of the Standard Model (SM). In this contribution a new analysis, using the latest experimental data, is…
We investigate a large class of supersymmetric SO(10) grand unified theories within the framework of gauge-mediated supersymmetry breaking. We start with the most general messenger sector and imbedd the standard model gauge group into…
In a recent paper, by working in the orbifold GUT limit of the Heterotic string, we showed how one could accommodate gauge coupling unification in the "mini-landscape" models of Lebedev et al. Furthermore, it was shown how one of the…
We investigate the quark-lepton symmetric gauge group in five dimensions, with the gauge symmetry broken by a combination of orbifold compactification of the extra dimension and the Higgs mechanism. The gauge sector of the model is…