Explicit construction of the pole part of the three-gluon vertex

We present an explicit construction of the special part of the three gluon vertex, which incorporates the Schwinger mechanism into the Schwinger-Dyson equation of the gluon propagator, enabling the generation of a dynamical gluon mass. This vertex contains massless, longitudinally coupled poles, acting effectively as composite Nambu-Goldstone bosons, generated by the strong QCD dynamics. The basic ingredients required for this construction are the longitudinal nature of this vertex and the Slavnov-Taylor identities that it must satisfy, in order for gauge-invariance and BRST symmetry to remain intact in the presence of a gluon mass.