  One-loop radiative Majorana neutrino masses through the exchange of scalars
have been considered for many years. We show for the first time how such a
one-loop mass is also possible through the exchange of vector gauge bosons. It
is based on a simple variation of a recently proposed $SU(2)_N$ extension of
the standard model, where a vector boson is a candidate for the dark matter of
the Universe.
