  We discuss some of the signatures associated with extensions of the Standard
Model related to the neutrino and electroweak symmetry breaking sectors, with
and without supersymmetry. The topics include a basic discussion of the theory
of neutrino mass and the corresponding extensions of the Standard Model that
incorporate massive neutrinos; an overview of the present observational status
of neutrino mass searches, with emphasis on solar neutrinos, as well the as
cosmological data on the amplitude of primordial density fluctuations; the
implications of neutrino mass in cosmological nucleosynthesis, non-accelerator,
as well as in high energy particle collider experiments. Turning to the
electroweak breaking sector, we discuss the physics potential for Higgs boson
searches at LEP200, including Majoron extensions of the Standard Model, and the
physics of invisibly decaying Higgs bosons. We discuss the minimal
supersymmetric Standard Model phenomenology, as well as some of the laboratory
signatures that would be associated to models with R parity violation,
especially in Z and scalar boson decays.
