Related papers: A cosmotopological relation for a unified field th…
We all know that in our family of particle physics we have three generations but still don't know why - the so-called "family problem". On other hand, in view of the masses and oscillations, the neutrinos now present some basic difficulty…
We discuss some consequences of the fact that symmetry groups appearing in compactified (super-)gravity may be non-simply connected. The possibility to add fermions to a theory results in a simple criterion to decide whether a 3-dimensional…
In the context of the free-fermionic formulation of the heterotic superstring, we construct a three generation N=1 supersymmetric SU(4)xSU(2)LxSU(2)R model supplemented by an SU(8) hidden gauge symmetry and five Abelian factors. The…
A new supersymmetric grand unified model based on the gauge group $SU(5)\times SU(5)$ is discussed. The model has the feature that the conventional seesaw mechanism for neutrino masses is implemented using the $(15, 1)+(1,\bar{15)}$…
A set of Grand Unified Theories based upon the gauge groups $SU(5)_\L \times SU(5)_\R$, $SO(10)_\L \times SO(10)_\R$ and $SU(4)_\C \times SU(4)_\L \times SU(4)_\R$ is explored. Several novel features distinguish these theories from the…
We discuss a supersymmetric grand unified model which has gauge group SU(5) $\times$ SU(5) $\times$ SU(5), with matter fields transforming asymmetrically under different gauge SU(5) groups. We observe that the gauge structure of the model…
We formulate an $SU(8)$ family unification model motivated by requiring that the theory should incorporate the graviton, gravitinos, and the fermions and gauge fields of the standard model, with boson--fermion balance. Gauge field $SU(8)$…
We consider the unification of gauge, Higgs as well as the matter fields in a 6D N=2 supersymmetric SU(8) gauge theory. The gauge symmetry SU(8) is broken down to SU(4) x SU(2)_L x SU(2)_R x U(1)^2 in 4D through T^2/Z_6 orbifold…
In grand unified theories with gauge groups larger than SU(5), the multiplets that contain the known quarks and leptons also contain fermions that are singlets under the Standard Model gauge group. Some of these could be the dark matter of…
It is set manifest an underlying algebraic structure of Dirac equation and solutions, in terms of Cl2 Clifford algebra projectors and ladder operators. From it, a scheme is proposed for constructing unified field theories by enlarging the…
The idea of grand unification in a minimal supersymmetric SU(5)xSU(5) framework is revisited. It is shown that the unification of gauge couplings into a unique coupling constant can be achieved at a high-energy scale compatible with proton…
The fermionic sector of the Standard Model of Elementary Particles emerges as the low energy limit of a single fermionic field freely propagating in a higher dimensional background. The local geometrical framework is obtained by enforcing…
A direct consequence of the occurrence of fermion families is the invariance of currents under certain groups of (universality) transformations. We show how these universality groups can themselves be used to find and study grand family…
It is noted that a set of facts points to the relevance in four dimensions of conventional supersymmetric unification based on minimally a string-unified G(224)-symmetry, or maximally SO(10). These include: (i) the observed family-…
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…
The Standard Model is based on the gauge invariance principle with gauge group U(1)xSU(2)xSU(3) and suitable representations for fermions and bosons, which are begging for a conceptual understanding. We propose a purely gravitational…
An ${\rm SU}(8)$ theory was previously found to be the minimal simple gauge group where all three-generational Standard Model (SM) fermions can be nontrivially embedded. It is maximally broken into a subgroup of ${\rm SU}(8)\to {\cal…
We study the possibility of complete family unification in higher-dimensional space-time. Three families of matters in SU(5) grand unified theory are derived from a single bulk multiplet of SU(N) gauge group (N >= 9) in the framework of…
We briefly review the issues of proton decay and fermion masses and mixings in minimal supersymmetric grand unified theories. We argue that minimal SU(5), although tightly constrained by proton decay data, is still not ruled out. However,…
We obtain a supersymmetric three family chiral SU(6) grand unification model with the global family symmetry SU(3)[family] from F-theory. This model has nice features such as all the fermion masses are reasonably generated and there results…