Related papers: Two-loop renormalization group analysis of supersy…
We investigate the viability of predictive schemes for quark-lepton Yukawa ratios and nucleon decay in non-supersymmetric SU(5) Grand Unified Theories (GUTs) where neutrino masses are generated by a type II seesaw mechanism. The scalar…
We examine gauge and Yukawa coupling unification in models with gauge-mediated supersymmetry breaking. We work consistently to two-loop order, and include all weak, messenger and unification-scale threshold corrections. We find that…
We show that one of the ways of obtaining consistency between the idea of supersymmetric grand unification and an apparent low value of $\alpha_{strong}(M_Z)\simeq .11$ indicated by several low energy experiments is to have an intermediate…
We study a prediction on neutrino observables in a non-supersymmetric renormalizable $SO(10)$ GUT model that contains a ${\bf 10}$ complex scalar field and a ${\bf 126}$ scalar field whose Yukawa couplings with ${\bf 16}$ matter fields…
We examine a superpotential for an SO(10) GUT and show that if the parameters of the superpotential are in a certain region, the SO(10) GUT has an intermediate symmetry ${\rm SU(2)}_L \otimes {\rm SU(2)}_R \otimes {\rm SU(3)}_C \otimes {\rm…
In this talk I briefly review the status of SUSY GUTs in 4, 5, 6 and 10 dimensions, focusing on the issue of gauge coupling unification and proton decay. I then discuss the predictions of the minimal SO(10) SUSY model [MSO$_{10}$SM].
We consider the breaking of the grand unification group $SO(10)$ to the standard model gauge group through several chains containing two intermediate stages. Using the values of the gauge coupling constants at scale $M_Z$ derived from…
The one-loop evolution of Yukawa couplings in the minimal supersymmetric left-right model (MSUSYLR) model with a wide variation of the right handed breaking scale $M_R$ from 1 TeV to $10^{18}$ GeV is studied assuming that all third…
One way to generate an intermediate scale being consistent with gauge coupling unification is to add new Higgs scalars above the intermediate scale. We classify such scenarios according to their degree of departure from minimal…
Supersymmetric grand unified models based on SO(10) gauge symmetry have many desireable features, including the unification of Yukawa couplings. Using D-term contributions to scalar masses arising from the breakdown of SO(10), Yukawa…
We investigate the renormalization group evolution of fermion masses, mixings and quartic scalar Higgs self-couplings in an ${\it extended}$ non-supersymmetric SO(10) model, where the Higgs sector contains the ${\bf 10}_{\rm H}$, ${\bf…
Non-renormalizable operators both account for the failure of down quark and charged lepton Yukawa couplings to unify and reduce the proton decay rate via dimension-five operators in minimal SUSY SU(5) GUT. We extend the analysis to SUSY…
We analyse the two-loop renormalization group (RG) flow of the gauge and Yukawa couplings within the E6 inspired supersymmetric (SUSY) models with extra U(1)_{N} gauge symmetry under which right-handed neutrinos have zero charge. In these…
We extend the nonsupersymmetric SO(10) grand unification theories by adding a horizontal symmetry, which connects the three generations of fermions. Without committing to any specific symmetry group, we investigate the 1-loop…
We investigate the effects of Yukawa couplings on the phenomenological predictions for a class of supersymmetric models which allows for the presence of complete SU(5) multiplets in addition to the Minimal Supersymmetric Standard Model…
We calculate the proton lifetime and discuss topological defects in a wide class of non-supersymmetric (non-SUSY) $SO(10)$ and $E(6)$ Grand Unified Theories (GUTs), broken via left-right subgroups with one or two intermediate scales (a…
Supersymmetric gauge theories, in higher dimensions compactified in an orbifold, give a natural framework to unify the gauge bosons, Higgs fields and even the matter fields in a single multiplet of the unifying gauge symmetry. The extra…
An analysis of generating fermion masses via cubic couplings in SO(10) grand unification with a unified Higgs sector is given. The new framework utilizes a single pair of vector--spinor representation $144+\bar{144}$ to break the gauge…
We investigate the status of predictive fermion mass ansatzes which make use of the grand unification scale conditions $m_e=m_d/3$, $m_\mu =3m_s$, and $\mid V_{cb}\mid =\sqrt{m_{c}/m_{t}}$ in non-supersymmetric SO(10) grand unification. The…
Supersymmetric SO(10) Grand Unified Theories with Yukawa unification represent an appealing possibility for physics beyond the Standard Model. However Yukawa unification is made difficult by large threshold corrections to the bottom mass.…