Related papers: GUT Inflation and Proton Decay after WMAP5
The logarithmic running of the gauge couplings alpha_1, alpha_2 and alpha_3, indicates that they may unify at some scale M_GUT ~ 10^16. This is often taken to imply that the standard model gauge group is embedded into some larger simple…
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 implement inflation within a realistic supersymmetric SO(10) model in which the doublet-triplet splitting is realized through the Dimopoulos-Wilczek mechanism, the MSSM $\mu$ problem is resolved, and higgsino mediated dimension five…
We compute the beta-functions of the standard model formulated on a noncommutative spacetime. If we assume that the scale for spacetime noncommutativity is of the order of 2.2 \times 10^{15} GeV we find that the three gauge couplings of the…
We propose a pseudo-Goldstone boson dark matter (pGDM) particle in $SO(10)$ grand unified theory (GUT). Due to its Goldstone nature, this pGDM evades the direct DM detection experiments which, otherwise, severely constrain the parameter…
After a brief review of the motivations for grand unification, I discuss the main challenges facing realistic SUSY GUT model building. Achieving doublet-triplet splitting without fine--tuning is chief among them. Symmetry breaking should…
This study revisits supersymmetric (SUSY) hybrid inflation in light of CMB experiments and swampland conjectures. We first show that if one adds radiative, soft mass, and SUGRA corrections to the scalar potential, supersymmetric hybrid…
We derive the threshold corrections in $\mathrm{SO}(10)$ grand unified models with the intermediate symmetry being flipped $\mathrm{SU}(5)\times\mathrm{U}(1)$ or $\mathrm{SU}(3)\times\mathrm{SU}(2)\times\mathrm{U}(1)\times\mathrm{U}(1)$,…
It is shown that non-renormalizable gravitational interactions in the Higgs sector of supersymmetric grand unified theories (GUT's) can produce the breaking of the unifying gauge group $G$ at the GUT scale $M_{\rm GUT} \sim 10^{16}$~GeV.…
Proton decay is one of the most important predictions of the grand unified theory (GUT). In the supersymmetric (SUSY) GUT, proton decays via the dimension-five operators need to be suppressed. In the $SO(10)$ model where ${\bf…
At the end of inflation the universe is frozen in a near zero-entropy state with energy density in a coherent scalar field and must be ``defrosted'' to produce the observed entropy and baryon number. We propose that the baryon asymmetry is…
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…
We explore some experimentally testable predictions of an $SO(10)$ axion model which includes two 10-plets of fermions in order to resolve the axion domain wall problem. The axion symmetry can be safely broken after inflation, so that the…
Supersymmetric GUTs based on SO(10) gauge group are leading contenders to describe particle physics beyond the Standard Model. Among these the "New minimal supersymmetric SO(10) grand unified theory" (NMSGUT) based on Higgs system…
We discuss inflationary cosmology in a five dimensional SO(10) model compactified on $S^1/(Z_2\times Z_2')$, which yields $SU(3)_c\times SU(2)_L\times U(1)_Y\times U(1)_X$ below the compactification scale. The gauge symmetry $SU(5)\times…
We discuss how in $SO(10)$ grand unification an observable number density of topologically stable intermediate mass ( $\sim 10^{14}$ GeV) monopoles survive inflation driven by a Coleman-Weinberg potential and non-minimal coupling of the…
We consider a scenario of cosmological inflation coming from a grand unified theory in higher dimensional orbifold. Flatness of the potential is automatically guaranteed in this orbifold setup thanks to the nonlocality of the Wilson line on…
We discuss the smooth hybrid inflation scenario in the context of a simple supersymmetric SO(10) GUT in 5D orbifold. In this GUT model, the SO(10) gauge symmetry is broken down to the Pati-Salam (PS) gauge group, SU(4)$_c \times$ SU(2)$_L…
We consider a phenomenologically viable SO(10) grand unification model of the unification scale $M_G$ around $10^{16} $ GeV which reproduces the MSSM at low energy and allows perturbative calculations up to the Planck scale $M_P$ or the…
A realistic tribrid model of sneutrino inflation is constructed in an $R$-symmetric $SU(5)$ grand unified theory (GUT). To avoid the monopole problem, a pseudosmooth inflationary trajectory is generated with the help of an additional $Z_5$…