Related papers: Asymptotic Grand Unification: The SO(10) case
Higher-dimensional models of grand unification allow us to relate the top Yukawa coupling y_t to the gauge coupling g. The tree level relation y_t=g at the scale of grand unification implies, in the framework of the MSSM, a rather small…
Grand gauge-Higgs unification of five dimensional SU(6) gauge theory on an orbifold $S^1/Z_2$ with localized gauge kinetic terms is discussed. The Standard model (SM) fermions on the boundaries and some massive bulk fermions coupling to the…
As an illustration of a renormalizable, asymptotically-free model of induced gravity, we consider an $SO(10)$ gauge theory interacting with a real scalar multiplet in the adjoint representation. We show that dimensional transmutation can…
The supersymmetric SO(10) GUT with $t$--$b$--$\tau$ Yukawa coupling unification has problems with correct electroweak symmetry breaking, experimental constraints (especially $b\rightarrow s\gamma$) and neutralino abundance, if the scalar…
We propose a realistic flipped SU(5) model derived from a five-dimensional orbifold SO(10) model. The Standard Model (SM) fermion masses and mixings are explained by combining the traditional Froggatt-Nielsen mechanism with the…
We present a Z_6 orbifold compactification of the E_8xE_8 heterotic string which leads to the (supersymmetric) Standard Model gauge group and matter content. The quarks and leptons appear as three 16-plets of SO(10), whereas the Higgs…
We make a detailed study of the unification of gauge couplings in the MSSM with large extra dimensions. We find some scenarios where unification can be achieved (with the strong coupling constant at the Z mass within one standard deviation…
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 talk we assume SO(10) boundary conditions at the GUT scale, including unification for the third generation Yukawa couplings $\lambda_t = \lambda_b = \lambda_\tau$. We find that this assumption is only consistent with the low energy…
O(10) grand unification models which do not necessarily have an extra global symmetry are discussed, taking the model with one 10-plet in the Yukawa sector as an example. A strong correlation between mass ratios and CP is found. The mass…
We investigate the status of predictive fermion mass ansatzes which make use of the grand unification scale conditions $m_e=m_d/3$, $m_\mu =3m_s$, and $\mid V_{cb}\mid =\sqrt{m_{c}/m_{t}}$ in non-supersymmetric SO(10) grand unification. The…
We desribe in detail a Z_6 orbifold compactification of the heterotic E_8 x E_8 string which leads to the (supersymmetric) standard model gauge group and matter content. The quarks and leptons appear as three 16-plets of SO(10), two of…
We investigate the prospects to achieve unification of the gauge couplings in models without supersymmetry. We restrict our discussion to $SU(5), SO(10)$ and $E_6$ models that mimic the structure of the Standard Model as much as possible…
We construct a supersymmetric standard model in the context of the Z_{12-I} orbifold compactification of the E_8 x E_8' heterotic string theory. The gauge group is SU(3)_c x SU(2)_L x U(1)_Y x U(1)^4 x [SO(10) x U(1)^3]' with sin^2\theta_W…
We perform numerical fits of Grand Unified Models based on SO(10), using various combinations of 10-, 120- and 126-dimensional Higgs representations. Both the supersymmetric and non-supersymmetric versions are fitted, as well as both…
We present the first example of a grand unified theory (GUT) with a modular symmetry interpreted as a family symmetry. The theory is based on supersymmetric $SU(5)$ in 6d, where the two extra dimensions are compactified on a…
Simple supersymmetric SO(10) GUT in five dimensions is proposed, in which the fifth dimension is compactified on the $S^1/(Z_2\times Z_2^\prime)$ orbifold with two inequivalent branes at the orbifold fixed points. In this model, all matter…
We study the breaking of a supersymmetric SO(10) GUT in 6 dimensions by orbifold compactification. In 4 dimensions we obtain a N=1 supersymmetric theory with the standard model gauge group enlarged by an additional U(1) symmetry. The…
Recently it has been proposed that, in the framework of quantum field theory, both the Standard Model gauge and Yukawa interactions arise from a single gauge interaction in higher dimensions with supersymmetry. This leads to the unification…
This report is a review of the present status of GUT, especially renormalizable minimal SO(10) GUT, and its future prospect. It consists of two parts. In part I, I review how the minimal renormalizable supersymmetric SO(10) GUT, an SO(10)…