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 (vBLβ) (corresponding to
B-L symmetry breaking) around the invisible axion scale of about 1011 -
1012 GeV. Such a scale is also desirable if Ξ½Οβ 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 bβΟ unification which is a successful
prediction of many grand unified theories is then required of these models and
the resulting prediction of b-quark mass is used as a measure of viability of
these schemes. Detailed analysis of a model with a vBLββ1011 GeV,
which satisfies both the requirements of invisible axion and Ξ½Οβ as
HDM is presented and shown to lead to mbββ4.9 GeV in the one-loop
approximation.Comment: Latex file; 20 pages; Four figures available on reques