  We consider a non-standard generalized model of gravity coupled to a neutral
scalar "inflaton" as well as to the fields of the electroweak bosonic sector.
The essential new ingredient is employing two alternative non-Riemannian
space-time volume-forms (non-Riemannian volume elements, or covariant
integration measure densitities) independent of the space-time metric. The
latter are defined in terms of auxiliary antisymmentric tensor gauge fields,
which although not introducing any additional propagating degrees of freedom,
trigger a series of important features such as: (i) appearance of two
infinitely large flat regions of the effective "inflaton" potential in the
corresponding Einstein frame with vastly different scales corresponding to the
"early" and "late" epochs of Universe's evolution; (ii) dynamical generation of
Higgs-like spontaneous symmetry breaking effective potential for the
SU(2)\times U(1) iso-doublet electroweak scalar in the late universe, whereas
it remains massless in the "early" universe. Next, to stabilize the
quintessential dynamics, we introduce in addition a coupling of the "inflaton"
to Gauss-Bonnet gravitational term. The latter leads to the following radical
change of the form of the total effective "inflaton" potential: its flat
regions are now converted into a local maximum corresponding to a "hill-top"
inflation in the "early" universe with no spontaneous breakdown of electroweak
gauge symmetry and, correspondigly, into a local minimum corresponding to the
"late" universe evolution with a very small value of the dark energy and with
operating Higgs mechanism.
