Related papers: Finite Unification: Theory and Predictions
The grand unified theories are theoretically well motivated, but they typically have less direct indications on the low energy physics and it is not easy to test them. Here, we discuss a scenario of them which naturally solves the so-called…
The SU(5) grand unified theory (GUT) is derived from the geometrical point of view of gauge theory on three-sheeted space-time, i.e., $M_4 \times Z_3$ manifold without recourse to noncommutative geometry. A derivation of SO(10) GUT is also…
We consider a theory with the gauge group $E_8$ assuming that the gauge symmetry breaking pattern is $E_8 \to E_7 \times U_1 \to E_6 \times U_1 \to SO_{10} \times U_1 \to SU_5 \times U_1 \to SU_3 \times SU_2 \times U_1$ and vacuum…
Maximally supersymmetric SO(10) and SU(6) unified theories are constructed on the orbifold T^2/(Z_2 x Z'_2), with one length scale R_5 taken much larger than the other, R_6. The effective theory below 1/R_6 is found to be the highly…
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…
The determination of the most straightforward evidence for the existence of the Superworld requires a guide for non-experts (especially experimental physicists) for them to make their own judgement on the value of such predictions. For this…
An analytical formalism, including RG running at two loop order, is used to link the supersymmetric and GUT spectra in any GUT model in which the three gauge couplings unify. In each specific GUT model, one can then fully explore the…
We perform a detailed investigation of a Grand Unified Theory (GUT)-inspired theory of gauge-Higgs unification. Scanning the model's parameter space with adapted numerical techniques, we contrast the scenario's low energy limit with…
D3-brane probes of exceptional Yukawa points in F-theory GUTs are natural hidden sectors for particle phenomenology. We find that coupling the probe to the MSSM yields a new class of N = 1 conformal fixed points with computable infrared…
We apply the orbifold grand unified theory (GUT) mechanism to the noncommutative Higgs model. An assignment of $Z_{2}$ parity to the "constituent fields" induces parity assignments of both the gauge and Higgs bosons, because these bosons…
Within the context of traditional logarithmic grand unification at M_GUT = 10^(16) GeV, we show that it is nevertheless possible to observe certain GUT states such as X and Y gauge bosons at lower scales, perhaps even in the TeV range. We…
We study unification in the Randall-Sundrum scenario for solving the hierarchy problem, with gauge fields and fermions in the bulk. We calculate the one-loop corrected low-energy effective gauge couplings in a unified theory, broken at the…
Standard (level one) heterotic string models with standard model gauge group predict the unification of $SU(3)$ and $SU(2)$ gauge couplings whereas the $U(1)$ factor is unified modulo an unknown normalization factor $k_1$. On the other hand…
This is a pedagogical review article surveying the various approaches towards understanding gauge coupling unification within string theory. As is well known, one of the major problems confronting string phenomenology has been an apparent…
This is the introduction to the collection of review articles "Exact results on N=2 supersymmetric gauge theories". The first three sections are intended to give a general overview over the physical motivations behind this direction of…
First we review Veltman's suggestion to attack the naturalness problem in the Standard model by requiring absence of quadratic divergences and the resulting mass formula. Then we emphasise the influence of Veltman's suggestion in…
In N=1 supersymmetric U(N) gauge theory with adjoint matter $\Phi$ and polynomial tree-level superpotential $W(\Phi)$, the massless fluctuations about each quantum vacuum are generically described by $U(1)^n$ gauge theory for some n.…
Within the gauge-theoretic approach of gravity, the gauging of an enlarged symmetry of the tangent space in four dimensions allows gravity to be unified with internal interactions. We study the unification of the conformal and…
In N = 1 super Yang-Mills theories, under certain conditions satisfied by the spectrum and the Yukawa couplings, the beta functions will vanish to all orders in perturbation theory. We address the generation of realistic quark mixing angles…
We examine the vacuum stability of gauge symmetry breaking in five dimensions, compactified on the $S_1/(\mathbb{Z}_2 \times \mathbb{Z}'_2)$ orbifold. We consider $SU(N)$, $Sp(N)$, $SO(2N)$ and $SO(2N+1)$ theories in the bulk, and provide…