Soft breaking of BRST invariance for introducing non-perturbative infrared effectsin a local and renormalizable way

摘要

The possibility of introducing non-perturbative infrared effects leading to a modification of the longdistance behavior of gauge theories through a soft breaking of the BRST invariance is investigated. Themethod reproduces the Gribov-Zwanziger action describing the restriction of the domain of integration inthe Feynman path integral to the Gribov region and a model for the dynamical quark mass generation ispresented. The soft symmetry breaking relies on the introduction of BRST doublets and massive physicalparameters, which allow one to distinguish the infrared region from the ultraviolet one, within the sametheory.