A natural MSSM from a novel $\mathsf{SO(10)}$, Yukawa unification, light sparticles, and SUSY implications at LHC

Abstract

The $\mathsf{SO(10)}$ model with a heavy Higgs spectrum consisting of $\mathsf{560+\overline{560}}$ and a light Higgs spectrum consisting of $2\mathsf{\times 10+320}$ plet representations of $\mathsf{SO(10)}$ is unique among $\mathsf{SO(10)}$ models.,It has the remarkable property that VEVs of $\mathsf{560}$ and $\mathsf{\overline{560}}$ can simultaneously reduce the rank of the gauge group and further reduce the remaining symmetry down to the standard model gauge group. Additionally, on mixing with the light fields all the Higgs fields become heavy except for one pair of light Higgs doublets just as in MSSM. This model has not been fully explored thus far because of the technical difficulty of computing the couplings of the heavy and the light Higgs sectors, specifically the interaction $(\mathsf{560\times 560)\cdot 320}$ involving the coupling of tensor-spinors with a third rank ~mixed tensor $\mathsf{320}$. An explicit analysis of such couplings is given in this paper. Spontaneous symmetry breaking of the $\mathsf{SO(10)}$ symmetry is carried out reducing the gauge group to $\mathsf{SU(3)}_c\times \mathsf{SU(2)}_L\times \mathsf{U(1)}_Y$ with just one just pair of light Higgs. Thus a natural deduction of MSSM arises from the $\mathsf{SO(10)}$ model with no fine tuning needed. Further, it is shown that the light Higgs doublet of the model is a linear combination of the Higgs doublet fields of the $2\mathsf{\times 10}$ and the $\mathsf{320}$ Higgs fields. It is shown that in this class of $\mathsf{SO(10)}$ models $b-t-\tau$ unification can be achieved with $\tan\beta$ as low as 5-10. An analysis of the sparticle spectrum within ${\tilde g}$SUGRA renormalization group evolution is given which leads to a bi-modal sparticle spectrum consisting of a compressed low mass spectrum for sleptons and weakinos and a high mass spectrum of gluino, squarks, and heavy Higgs.LHC.