  The Minimal Supersymmetric extension of the Standard Model provides a
solution to the hierarchy problem and leads to the presence of a light Higgs. A
Higgs boson with mass above the present experimental bound may only be obtained
for relatively heavy third generation squarks, requiring a precise, somewhat
unnatural balance between different contributions to the effective Higgs mass
parameter. It was recently noticed that somewhat heavier Higgs bosons, which
are naturally beyond the LEP bound, may be obtained by enhanced weak SU(2)
D-terms. Such contributions appear in models with an enhanced electroweak gauge
symmetry, provided the supersymmetry breaking masses associated with the
scalars responsible for the breakdown of the enhanced gauge symmetry group to
the Standard Model one, are larger than the enhanced symmetry breaking scale.
In this article we emphasize that the enhanced SU(2) D-terms will not only
raise the Higgs boson mass but also affect the spectrum of the non-standard
Higgs bosons, sleptons and squarks, which therefore provide a natural
contribution to the T parameter, compensating for the negative one coming from
the heavy Higgs boson. The sleptons and non-standard Higgs bosons of these
models, in particular, may act in a way similar to the so-called inert Higgs
doublet. The phenomenological properties of these models are emphasized and
possible cosmological implications as well as collider signatures are
described.
