Related papers: Three-Family Models from a Heterotic Orbifold on t…
We will outline our recent efforts aimed at analysing a class of models known as orbifold GUTs and their phenomenology in a variety of minimal and non-minimal settings. We examine the minimal SU(5) models, rule them out, and proceed by…
A link is established between the observed (approximate) geometric mass hierarchy of quarks and leptons and the triangular structure of their tenable flavor representations. This singles out SU(3) as the horizontal flavor group, thereby…
This paper extends and builds upon the results of an earlier paper, in which we described how to use the tools of geometrical engineering to deform geometrically-engineered grand unified models into ones with lower symmetry. This top-down…
Eight-dimensional non-geometric heterotic strings with gauge algebra $\mathfrak{e}_8\mathfrak{e}_7$ were constructed by Malmendier and Morrison as heterotic duals of F-theory on K3 surfaces with $\Lambda^{1,1}\oplus E_8\oplus E_7$ lattice…
Many heterotic orbifold models have massless twisted-sector particles with simultaneous E8_1 and E8_2 charges. In the strong-coupling M-theory dual of the heterotic string this poses a paradox: Since the E8_1 and E8_2 live at opposite ends…
We show how to construct supersymmetric three-generation models with gauge group and matter content of the Standard Model in the framework of non-simply-connected elliptically fibered Calabi-Yau manifolds Z. The elliptic fibration on a…
By considering the 3-3-1 and the left-right symmetric models as low energy effective theories of the $SU(3)_C\otimes SU(3)_L\otimes SU(3)_R$~(for short $[SU(3)]^3$) gauge group, alternative versions of these models are found. The new…
Based on a specific model with U(3) family gauge symmetry at $10^3$ TeV scale, we show its experimental signatures to search for. Since the gauge symmetry is introduced with a special purpose, its gauge coupling constant and gauge boson…
The first particle physics observable whose origin may be sought in string theory is the triple replication of the matter generations. The class of Z2XZ2 orbifolds of six dimensional compactified tori, that have been most widely studied in…
We analyze heterotic line bundle models on elliptically fibered Calabi-Yau three-folds over weak Fano bases. In order to facilitate Wilson line breaking to the standard model group, we focus on elliptically fibered three-folds with a second…
It is well-known that three-family supersymmetric Pati-Salam models from intersecting D6-branes, where either one or both of the ${\rm U}(2)$ gauge factors are replaced by a ${\rm USp}(2)$ group, are quite scarce. In order to construct all…
Combining a semi-classical analysis with exact diagonalizations, we show that the ground state of the SU(3) Heisenberg model on the square lattice develops three-sublattice long-range order. This surprising pattern for a bipartite lattice…
We propose an SU(5) SUSY GUT of flavour with A_4 family symmetry in 8d where the vacuum alignment is achieved in an elegant way by the use of boundary conditions on orbifolds. The model involves SU(5) living in the 8d bulk, with matter…
Standard SUSY-GUTs such as those based on $SU(5)$ or $SO(10)$ lead to predictions for the values of $\alpha _s$ and $sin^2\theta _W$ in amazing agreement with experiment. In this article we investigate how these models may be obtained from…
The mass and weak interaction eigenstates for the quarks of the third generation are very well aligned, an empirical fact for which the Standard Model offers no explanation. We explore the possibility that this alignment is due to an…
A discrete symmetry S3 easily explains all neutrino data. However it is not obvious the embedding of S3 in GUT where all fermions live in the same representation. We show that embedding S3 in E6 it is possible to make distinction between…
We consider the F-theory description of non-simply-connected gauge groups appearing in the E8 x E8 heterotic string. The analysis is closely tied to the arithmetic of torsion points on an elliptic curve. The general form of the…
SU(3) gauge theory coupled to N_f = 2 fermions in the sextet representation is a promising candidate for a technicolor inspired Standard Model extension. In this note the progress in the past few years aimed at understanding the…
We propose stacked two-dimensional lattice designs of frustrated and SO(3) symmetric spin models consisting of antiferromagnetic (AFM) triangular and ferromagnetic (FM) sixfold symmetric sublattices that realize emergent Z3 Potts nematic…
The heterotic string free fermionic formulation produced a large class of three generation models, with an underlying SO(10) GUT symmetry which is broken directly at the string level by Wilson lines. A common subset of boundary condition…