  Recently proposed extension of Yang-Mills theory contains non-Abelian tensor
gauge fields. The Lagrangian has quadratic kinetic terms, as well as cubic and
quartic terms describing non-linear interaction of tensor gauge fields with the
dimensionless coupling constant. We analyze particle content of non-Abelian
tensor gauge fields. In four-dimensional space-time the rank-2 gauge field
describes propagating modes of helicity 2 and 0. We introduce interaction of
the non-Abelian tensor gauge field with fermions and demonstrate that the free
equation of motion for the spin-vector field correctly describes the
propagation of massless modes of helicity 3/2. We have found a new
metric-independent gauge invariant density which is a four-dimensional analog
of the Chern-Simons density. The Lagrangian augmented by this Chern-Simons-like
invariant describes massive Yang-Mills boson, providing a gauge-invariant mass
gap for a four-dimensional gauge field theory.
