  The nonlinear SU(2) electroweak model is used to explain the absence of the
right-handed neutrino in weak interactions. Two covariant eigenvalue
constraints which affect the transformation lead to two classes of right-handed
leptons, and make possible invariant mass terms without the Higgs doublet. A
covariant picture of neutrinos with mass is presented. A new invariant form for
the boson potentials is described in which the boson mass terms arises via the
adjoint field. This model also indicates a different region of matter involving
coupled leptons that are "blind" to the massless electromagnetic field but
"see" four massive potentials that are themselves blind to the electromagnetic
field. We argue that these more difficult to detect "dark" fields provide a
possible contribution to the missing mass.
