Related papers: Minimal SU(5) theory on the edge: the importance o…
Minimal $SU(5)$ Grand Unified models predict massless neutrinos and struggle to achieve gauge coupling unification compatible with the observed lower limit on the proton lifetime. Both of these issues can be resolved by embedding minimal…
We present phenomenological study of the most minimal realistic $SU(5)$ model that owns its predictivity solely to the gauge symmetry and the representational content. The model is built entirely out of the fields residing in the first five…
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 propose a simple renormalizable grand unified theory based on the $SU(5)$ gauge symmetry where the neutrino masses are generated at the quantum level through the Zee mechanism. In this model the same Higgs needed to correct the mass…
Nonsupersymmetric minimal SU(5) with Higgs representations ${24}_H$ and $5_H$ and standard fermions in ${\bar 5}_F\oplus {10}_F$ is well known for its failure in unification of gauge couplings and lack of predicting neutrino masses. Like…
We present phenomenological aspects of the simplest realistic SU(5) grand unified theory--the theory with the 5, 15, and 24 dimensional representations in the Higgs sector. We show that a successful gauge coupling unification sets…
We review the main constraints on the parameter space of the minimal renormalizable supersymmetric SU(5) grand unified theory. They consist of the Higgs mass, proton decay, electroweak symmetry breaking and fermion masses. Superpartner…
We investigate the unification constraints in the minimal sypersymmetric grand unified theories based on SU(5) gauge symmetry. The most general constraints on the spectrum of minimal supersymmetric SU(5) and flipped SU(5) are shown. The…
We investigate a simple realistic grand unified theory based on the $SU(5)$ gauge symmetry which predicts an upper bound on the proton decay lifetime for the channels $p \to K^+ \bar{\nu}$ and $p \to \pi^+ \bar{\nu}$, i.e. $\tau (p \to K^+…
I review the theoretical and experimental status of proton decay theory and experiment. Regarding theory, I focus mostly, but not only, on grand unification. I discuss only the minimal, well established SU(5) and SO(10) models, both…
A unified model is constructed, based on flipped $SU(5)$ in which the proton is absolutely stable. The model requires the existence of new leptons with masses of order the weak scale. The possibility that the unification scale could be…
I briefly outline the most prominent features of a novel $SU(5)$ unification model proposal. The particle content of the model comprises $5_H$, $24_H$, $35_H$, ${\overline{5}_F}_i$, ${10_F}_i$, $15_F$, $\overline{15}_F$, and $24_V$, where…
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…
A grand unified model based on SU(5) and supersymmetry is presented. Pairs of superfields belonging to 15 and 15* representations are newly introduced, while gauge coupling unification is satisfied. Improper mass relations in the minimal…
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…
It is a well-known fact that the minimal renormalizable supersymmetric SU(5) model is ruled out assuming superpartner masses of the order of a few TeV. Giving up this constraint and assuming only SU(5) boundary conditions for the soft…
We propose a simple $SU(5)$ model that connects the neutrino mass generation mechanism to the observed disparity between the masses of charged leptons and down-type quarks. The model is built out of $5$-, $10$-, $15$-, $24$-, and…
In this work we propose a renormalizable model based on the $SU(5)$ gauge group where neutrino mass originates at the two-loop level without extending the fermionic content of the Standard Model (SM). Unlike the conventional $SU(5)$ models,…
The minimal $SO(10)$ grand unified theory, augmented by higher-dimensional operators, is based on the following Higgs representations: adjoint $45_{\rm H}$, spinor $16_{\rm H}$ and complex vector $10_{\rm H}$. It was recently realized that,…
The issue of gauge unification in the (non-supersymmetric) Standard Model is reinvestigated. It is found that with just an additional fourth generation of non-sequential and long-lived quarks and leptons, SU(3)xSU(2)xU(1) gauge couplings…