Related papers: Planck-Scale Effects on Nucleon Decay in Minimal S…
Generic SO(10) GUT models suffer from the problem that Planck scale induced non-renormalizable proton decay operators require extreme suppression of their couplings to be compatible with present experimental upper limits. One way to resolve…
The SUSY $SO(10)$ GUT is in severe tension with the experimental bounds on proton partial lifetimes because proton decay mediated by colored Higgsinos (dimension-five proton decay) is too rapid. In this paper, we pursue the possibility that…
In supersymmetric grand unified theories (GUTs) based on S^1/(Z_2 x Z'_2) orbifold constructions in 5 dimensions, Standard Model (SM) matter and Higgs fields can be realized in terms of 5d hypermultiplets. These hypermultiplets can…
The radiative electroweak symmetry breaking, the b-\tau Yukawa and gauge couplings unification in the MSSM and its SU(5) extensions are studied in detail. In the framework of the two-loop renormalization group equations both low- and…
The consequences of assuming the third-generation Yukawa couplings are all large and comparable are studied in the context of the minimal supersymmetric extension of the standard model. General aspects of the RG evolution of the parameters,…
We give a detailed renormalization group analysis for the SU(16) grandunified group with general breaking chains in which quarks and leptons transform separately at intermediate energies. Our analysis includes the effects of Higgs bosons.…
We study the impact of multiple vector-like fermions in SU(5) grand unified theory (GUT). Threshold effects from extra fermions allow the observed gauge couplings to be consistently matched to a single unified gauge coupling, and typically…
We analyse proton decay in the context of simple supersymmetric SU(5) grand unified models with an extra compact spatial dimension described by the orbifold S^1/(Z_2 x Z_2'). Gauge and Higgs degrees of freedom live in the bulk, while matter…
In the supersymmetric grand unified theories (SUSY GUTs), gauge bosons associated with the unified gauge group induce proton decay. We investigate the proton decay rate via the gauge bosons in the SUSY GUTs under the two situations; one is…
By considering the constraints from nucleon decay we obtain upper limits on tan beta in generalized supersymmetric SU(5) grand unified theories with gauge-mediated supersymmetry breaking. We find that the predicted values of tan beta in…
We discuss how the double missing partner mechanism solution to the doublet-triplet splitting problem in four-dimensional supersymmetric SU(5) Grand Unified Theories (GUTs) can be combined with predictive models for the quark-lepton Yukawa…
We construct a supersymmetric grand unified model in which a dynamical symmetry breaking of SU(5)$_{GUT}$ generates large masses for color-triplet Higgs multiplets while keeping SU(2)$_L$-doublet Higgs multiplets naturally light. The…
A novel mechanism to realize the triplet-doublet splitting in supersymmetric SU(5) grand unified theories is proposed in the framework of higher dimensional theories where chiral multiplets are localized due to kink configuration of a SU(5)…
We perform a likelihood analysis of the constraints from accelerator experiments and astrophysical observations on supersymmetric (SUSY) models with SU(5) boundary conditions on soft SUSY-breaking parameters at the GUT scale. The parameter…
We study the breaking of supersymmetry and its transmission to the light states in the context of the minimal SU(5) grand unified theory, with no additional singlets. This simple theory can be taken as a prototype for a program of breaking…
We implement inflation in a supersymmetric SU(5) model with U(1) R-symmetry such that the cosmic microwave anisotropy $\delta T/T$ is proportional to $(M/M_{\rm Planck})^2$, where $M\sim M_{GUT}=2-3\times 10^{16}$ GeV, the SU(5) breaking…
In the last few years physicists have been looking at $SO(10)$ GUT models with renewed attention because it has been realized that the SU(5) minimal model cannot unify the strong, electromagnetic and weak interactions in a way consistent…
We present a detailed study of the decays of the Higgs bosons $H^+$, $H^0$, and $A^0$ within the Minimal Supersymmetric Standard Model including SUSY--QCD corrections. We find that the supersymmetric modes $\tilde t \bar{\tilde b}$ ($\tilde…
In supersymmetric Grand Unified Theories, proton decay mediated by the color--triplet higgsino is generally problematic and requires some fine--tuning of parameters. We present a mechanism which naturally suppresses such dimension 5…
We present an updated analysis of the Yukawa matrix unification within the renormalizable Minimal Supersymmetric Standard Model. It is assumed that the soft terms are non-universal but flavour-diagonal in the super-CKM basis at the GUT…