Related papers: Gauge coupling unification without leptoquarks
The standard model extended by three vector-like families with masses of order 1 TeV -- 100 TeV allows for unification of gauge couplings. The values of gauge couplings at the electroweak scale are highly insensitive to fundamental…
GUT scale threshold corrections in minimal SU(5) supergravity grand unification are discussed. It is shown that predictions may be made despite uncertainties associated with the high energy scale. A bound relating the strong coupling…
A constraint on masses of superheavy gauge and Higgs multiplets at the grand unification (GUT) scale is obtained from the gauge coupling unification in the case of high-scale supersymmetry. We found that all of the particles may lie around…
I investigate the phenomenology of supersymmetric models with extra vector-like supermultiplets that couple to the Standard Model gauge fields and transform as the fundamental representation of a new confining non-Abelian gauge interaction.…
We have recently proposed an alternative picture for the physics at the scale of gauge coupling unification, where the unified symmetry is realized in higher dimensions but is broken locally by a symmetry breaking defect. Gauge coupling…
Because of the problems arising from the fermion unification in the traditional Grand Unified Theory and the mass hierarchy between the 4-dimensional Planck scale and weak scale, we suggest the low energy gauge unification theory with low…
It was previously noted that SU(5) unification can be achieved via the simple addition of light scalar leptoquarks from two split $\bf10$ multiplets. We explore the parameter space of this model in detail and find that unification requires…
We discuss how a model for the electroweak interactions without a Higgs could be embedded into a grand unified theory. The requirement of a non-trivial fixed point in the SU(2) sector of the weak interactions together with the requirement…
A complete 5-dimensional SU(5) unified theory is constructed which, on compactification on the orbifold with two different Z_2's (Z_2 and Z_2'), yields the minimal supersymmetric standard model. The orbifold accomplishes SU(5) gauge…
We discuss gauge coupling unification in models with additional 1 to 4 complete vector-like families, and derive simple rules for masses of vector-like fermions required for exact gauge coupling unification. These mass rules and the…
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…
The alternative $SU(4) \otimes SU(2)_L \otimes SU(2)_R$ gauge model, which allows unification of the quarks and leptons at the TeV scale, is studied in detail. We discuss the implications for nucleon decay, B and K rare meson decays and…
The significant heavy threshold effect is found in the supersymmetric SU(5) model with two adjoint scalars, one of which is interpreted as a massive string mode decoupled from the lower-energy particle spectra. This threshold related with…
We investigate predictions of a minimal realistic non-supersymmetric SU(5) grand unified theory. To accomplish unification and generate neutrino mass we introduce one extra Higgs representation--a 15 of SU(5)--to the particle content of the…
We consider the scenario where all the couplings in the theory are strong at the cut-off scale, in the context of higher dimensional grand unified field theories where the unified gauge symmetry is broken by an orbifold compactification. In…
We investigate a 5D SU(6) grand gauge-Higgs unification model compactified on an orbifold S^1/Z_2. Ordinary quarks and leptons, together with right-handed neutrinos, are just accommodated into a minimal set of representations of the gauge…
We revisit the doublet-triplet splitting problem within the $SU(5)$ gauge group framework to advocate a viable regime with the light scalar leptoquark of the doublet-triplet splitting notoriety that is compatible with the current…
We construct a four-dimensional SU(5) grand unified theory in which the proton is stable. The Standard Model leptons reside in the 5 and 10 irreps of SU(5), whereas the quarks live in the 40 and 50 irreps. The SU(5) gauge symmetry is broken…
We present a supersymmetric grand unification scheme based on the gauge group SU(3)_c X SU(3)_L X SU(3)_R in which the proton and the lightest supersymmetric particle are stable, neutrinos are necessarily massive, and the observed baryon…
The apparent unification of gauge couplings in Grand Unified Theories around 10$^{16}$ GeV is one of the strong arguments in favor of Supersymmetric extensions of the Standard Model. In this paper, an analysis of the measurements of the…