6 research outputs found
Intermediate Scales in SUSY SO(10), b-\tau unification and Hot Dark Matter Neutrinos
Considerations of massive neutrinos, baryogenesis as well as fermion mass
textures in the grand unified theory framework provide strong motivations for
supersymmetric(SUSY) SO(10) as the theory beyond the standard model. If one
wants to simultaneously solve the strong CP problem via the Peccei-Quinn
mechanism, the most natural way to implement it within the framework of the
SUSY SO(10) model is to have an intermediate scale () (corresponding to
B-L symmetry breaking) around the invisible axion scale of about 10 -
10 GeV. Such a scale is also desirable if is to constitute
the hot dark matter (HDM) of the universe. In this paper, we discuss examples
of superstring inspired SUSY SO(10) models with intermediate scales that are
consistent with the low energy precision measurements of the standard model
gauge couplings. The hypothesis of unification which is a successful
prediction of many grand unified theories is then required of these models and
the resulting prediction of -quark mass is used as a measure of viability of
these schemes. Detailed analysis of a model with a GeV,
which satisfies both the requirements of invisible axion and as
HDM is presented and shown to lead to GeV in the one-loop
approximation.Comment: Latex file; 20 pages; Four figures available on reques
Effects of 126 dimensional Higgs scalar on Bottom-Tau unification and quasi-infrared fixed point
In the presence of Higgs multiplets in a SO(10)
theory, the fermion masses get contributions from an induced vacuum expectation
value (VEV) of a doublet residing in 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.Comment: revised version with same conclusions. To appear in Phys. Rev.