Speaker
Description
We present a thorough analysis of dynamical gluon mass generation under the lens of operatorial BRST quantization of linear covariant gauges. We show that, when a gluon mass is dynamically generated, a massless colored scalar takes the place of the longitudinal gluon polarization as the first parent of the elementary BRST quartet. The scalar can be interpreted as an unphysical bound-state superposition of two gluons, three gluons, a ghost-antighost pair, and a quark-antiquark pair, and it triggers the Schwinger mechanism responsible for gluon mass generation. Moreover, it is the Goldstone boson associated to the spontaneous breaking of the global gauge (color) charge. Despite the failure of the Kugo-Ojima criterion, an unbroken BRST-exact color charge operator can be still uniquely identified that realizes color confinement in the sense of the absence of colored asymptotic states from the BRST cohomology. The confinement mechanism is dynamical: indeed, it is the non-abelian generalization of the Schwinger mechanism.