  A new topological field theory is constructed, which is characterized by
cubic interactions similar to those of non-abelian Chern-Simons field theories,
but still retains the simplicity of the abelian case. The perturbative
expansion of this theory contains in fact only two connected Feynman diagrams,
the propagator and a three vertex. Apart from the Gauss linking number, the
Wilson loop amplitudes generate a further topological invariant, whose physical
and mathematical meaning is investigated.
