Effects of 126 dimensional Higgs scalar on Bottom-Tau unification and quasi-infrared fixed point

Abstract

In the presence of $126+\overline{126}$ Higgs multiplets in a SO(10) theory, the fermion masses get contributions from an induced vacuum expectation value (VEV) of a $SU(2{)}_L$ doublet residing in $126$ which differentiates between quarks and leptons by a relative sign leading to a significant correction to the prediction of the mass ratio of the bottom quark and the tau lepton for ranges of the mass of this extra doublet. We perform a two-loop renormalization group analysis of the minimal version of the one-step supersymmetric SO(10) model to display this and re-calculate the corrections to the top quark mass in the presence of such an induced VEV. We show that these effects make the infra-red fixed point scenario consistent with experimental results.

Comments: revised version with same conclusions. To appear in Phys. Rev. D