2+Nonet as Gauge Particles forSL(6, C)Symmetry

We construct an $\mathrm{SL}(6, C)$ gauge-invariant Lagrangian which describes a nonet of massive positive-energy $2^{+}$ particles. Of importance for the model are the concepts of covariant constraint and spontaneous symmetry breaking. The distinguishing feature of the present theory is the set of conserved currents which generate the algebra of $\mathrm{SL}(6, C)$. We also present gauge-invariant and unitarity-preserving quark and meson (quark-antiquark composite) Lagrangians.