A theoretical study re-examines the Kugo-Ojima scenario for colour confinement in QCD and argues that dynamical gluon mass generation, described by the Schwinger mechanism in the formulation by Aguilar, Binosi, Ferreira and Papavassiliou (ABFP), is in fact a Higgs mechanism. According to the authors, this process occurs together with the spontaneous breaking of the global gauge charge, as it should, and the ABFP bound state appears as the associated (unphysical) composite Goldstone boson.

The starting point is a critical reassessment of the Kugo-Ojima scenario, in which the authors identify several inconsistencies and a crucial error in its derivation. Within that same framework, and under customary assumptions, they show that the BRST quartet structure incorporates a unique mechanism for dynamical gluon mass generation: the Schwinger mechanism. BRST symmetry takes over the role of the broken symmetry, while the colour symmetry of the spectrum remains unbroken.

The zero-momentum value of the gluon propagator, computed with the Pinch Technique combined with the Background-Field Method (PT-BFM), emerges naturally in the derivation and sets a renormalization-group invariant scale for mass generation. The authors interpret this result as a new non-perturbative reading of the PT-BFM. They also obtain a well-defined, BRST-exact and unbroken asymptotic colour charge operator that realises confinement in the sense of the absence of coloured asymptotic states from the BRST cohomology.

Still within the Kugo-Ojima framework, the work takes the first step towards a proof of the non-perturbative unitarity of the linear covariant gauges of QCD, discusses the experimental evidence in favour of the Schwinger mechanism, and lays the foundations for a unified theory of gauge-boson mass generation in the linear covariant gauges of Yang-Mills theories.