Related papers: Proton Stability, Dark Matter and Light Color Octe…
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…
Despite the successes of the Standard Model of particle physics, it is known to suffer from a number of deficiencies. Several of these can be addressed within non-supersymmetric theories of grand unification based on $\mathrm{SO}(10)$.…
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].
As has been previously proposed, a minimal modification of the standard $SU(3)\times SU(2)\times U(1)$ theory provides a viable dark matter candidate. Such a particle, a scalar gauge singlet, is naturally self-interacting---making it of…
We consider the constraints from proton decay and $b$-$\tau$ unification in the minimal supersymmetric SU(5) grand unified theory with a `visible' dynamical supersymmetry breaking sector. We show how the presence of vector-like messenger…
A fully realistic unified theory is constructed, with SU(5) gauge symmetry and supersymmetry both broken by boundary conditions in a fifth dimension. Despite the local explicit breaking of SU(5) at a boundary of the dimension, the large…
We propose an SU(5)$\times $U(1)$_\text{X}\times$U(1)$_\text{PQ}$ model without SUSY because the SUSY particles have not been observed yet. The $\mathrm{U(1)_{X}}$ gauge symmetry is the generalization of the $\mathrm{U(1)_{B-L}}$ gauge…
In this talk, we present a minimal viable scenario that unifies the gauge symmetries of the Standard Model (SM) and their breaking sector. Our Gauge-Higgs Grand Unification setup employs 5D warped space with a $SU(6)$ bulk gauge field that…
We consider the constraints on SO(10) unified models coming from the lower limits on proton lifetime and on the scale of B-L symmetry breaking within the framework of the seesaw model for neutrino masses. By upgrading a triangular…
Within a chiral $SU(15)$ gauge theory in which the Standard Model fermions are bound states of massless preons, we show that proton-decay operators are likely induced at the compositeness scale, $\Lambda_{\rm pre}$. Our estimate of the…
We consider proton stability based on E_6 inspired extra U(1) model with S_4 x Z_2 flavor symmetry. In this model, a long life time of proton is realized by the flavor symmetry in several ways. We classify the suppression mechanisms of…
In direct breaking of non-supersymmetric SO(10) to the standard model, we investigate the possibility that dark matter (DM) decaying through its mixing with right-handed neutrino (RH$\nu$) produces high energy IceCube neutrinos having…
The extended supersymmetric SO(10) model with missing partner mechanism is studied. An intermediate vacuum expectation value is incorporated which corresponds to the see-saw scale. Gauge coupling unification is not broken explicitly. Proton…
In a model of supersymmetric SU(5) Grand Unification with a spatial dimension described by the orbifold $S^1/(Z_2 \times Z_2')$, proton decay is naturally suppressed at all orders. This is achieved by a suitable implementation of the…
The presence of a colored scalar that is a weak doublet with fractional electric charges of $|Q|=2/3$ and $|Q|=5/3$ with mass below 1,TeV can provide an explanation of the observed branching ratios in $B \to D^{(*)} \tau \bar \nu$ decays.…
The well-studied radiative model of neutrino mass through $Z_2$ dark matter is shown to be naturally realizable in the context of SU(6) grand unification. A recent new proposal based on U(1)_D dark matter is similarly accommodated in SU(7).…
Supersymmetric (SUSY) grand unified theories (GUTs) appear to be best motivated for understanding strong, weak and electromagnetic interactions of nature. We briefly review emergence of new formulas for running fermion masses valid in…
By supplementing minimal supersymmetric SU(5) (MSSU(5)) with a flavor ${\cal U}(1)$ symmetry and two pairs of $\bar{15}+15$ `matter' supermultiplets, we present an improved model which explains the charged fermion mass hierarchies and 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…
We discuss how an anomalous U(1) symmetry when appended to MSSM and SUSY GUTs [e.g. SU(5)] can help overcome a variety of puzzles related to charged fermion masses and mixings, flavor changing processes, proton decay and neutrino…