Related papers: Dimension-six Proton Decays in the Modified Missin…
Evaluation of nucleon decay modes and branching ratios in a non-minimal supersymmetric SO(10) grand unified theory is presented. The non-minimal GUT considered is the supersymmetrised version of the `realistic' SO(10) model originally…
We propose to partially unify the sequential $SU(3)_c\times SU(3)_L\times U(1)_X$ model (with $\beta=1/\sqrt{3}$) into the flipped $SU(6)$ model with the gauge group $SU(6)\times U(1)_K$. Gauge anomaly cancellation can easily be satisfied.…
We present a class of realistic unified models based on supersymmetric SO(10) wherein issues related to natural doublet-triplet (DT) splitting are fully resolved. Using a minimal set of low dimensional Higgs fields which includes a single…
It is well known, although sometimes ignored, that not only the d=5 but also d=6 proton decay depends on fermion mixings. In general we study carefully the dependence of d=6 decay on fermion mixings using the effective operator approach. We…
Non-observation of proton decays as well as the smallness of the neutrino masses can naturally be explained by the accidental baryon and lepton number symmetry in the Standard Model, where the approximate symmetries are a consequence of the…
Two-loop evolutions of the gauge couplings in a class of intermediate scale supersymmetric SO(10) models including the effect of third generation Yukawa couplings are studied. The unification scale, the intermediate scale and the value of…
In this work I present a full analysis of proton decay in an $SO(10)$ model previously proposed by Dutta, Mimura, and Mohapatra. The $\bf{10}$, $\overline{\bf{126}}$, and $\bf{120}$ Yukawa couplings contributing to fermion masses in this…
Proton decay within 5-dimensional SU(6) GUT with orbifold S^1/Z_2 breaking is investigated using Scherk-Schwarz mechanism. It is shown that in the model neither leptoquark like heavy gauge bosons nor violation of baryon number conservation…
We show that in supersymmetric unified theories such as SO(10), implementation of the see-saw mechanism for neutrino masses introduces a new set of color triplet fields and thereby a new source of d=5 proton decay operators. For neutrino…
We present a minimal non-supersymmetric SO(10) GUT breaking directly to the Standard Model gauge group. Precise gauge coupling unification is achieved due to the presence of two color-octet scalars, one of which is accessible to LHC…
The half-life of the 2 neutrino double-beta-decay of 160Gd, a process which was previously reported as theoretically forbidden, is estimated by including the pairing interaction, which mixes different occupations and opens channels for the…
We construct a supersymmetric grand unified model in the framework of a latticized extra dimension. The SU(5) symmetries on the lattice are broken by the vacuum expectation values of the link fields connecting adjacent SU(5) sites, leaving…
In the Standard Model, no dim-5 $\Delta B \neq 0$ operators exist, so that Planck-scale-induced proton decay amplitudes are suppressed by at least $1/M^2_{P \ell}$. If the Standard Model is augmented by a light, color-non-singlet boson,…
Proton decay is usually discussed in the context of grand unified theories. However, as is well-known, in the standard model effective theory proton decay appears in the form of higher dimensional non-renormalizable operators. Here, we…
We show that the prediction for $\alpha_s(M_Z)$ in flipped SU(5) is naturally lower than in minimal SU(5), and that the former can accommodate the full range of $\alpha_s(M_Z)$ presently allowed by experiment. Our computations include…
We show that in supersymmetric grand unified theories new effective D=4 and D=5 operators for proton decay are induced by soft SUSY-breaking terms, when heavy GUT gauge bosons are integrated out, in addition to the standard D=6 ones. As a…
We present our best estimates of the uncertainties due to heavy particle threshold corrections on the unification scale $M_U$, intermediate scale $M_I$ and coupling constant Alpha_U in the minimal non-supersymmetric SO(10) models. Using…
We study the influence of messenger Yukawa couplings and top, bottom and $\tau$ Yukawa couplings on the proton lifetime in SU(5) Supersymmetric GUT with dynamical supersymmetry breaking mechanism due to Dine and Nelson.
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…
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…