  The appearance of a broken supersymmetric U(1) gauge factor at the TeV scale
is relevant for several reasons. If it truly exists, then one important
consequence is that at the 100 GeV energy scale, the two-doublet Higgs
structure is of a more general form than that of the Minimal Supersymmetric
Standard Model (MSSM). This is a prime example of tree-level nondecoupling.
Furthermore, a particular U(1)_N from the superstring-inspired E_6 model allows
for the existence of naturally light singlet neutrinos which may be necessary
to accommodate the totality of neutrino-oscillation experiments.
