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SS18 – Abstract
David Dudal
(Leuven)
12.4.2018
Using the horizon beyond the Landau gauge
A possible way to deal with (small) Gribov copies in the Landau gauge is to restrict the domain of integration of the gauge field variables. Such pioneering work was carried out by Gribov himself at leading order, and improved upon to all orders by Zwanziger, an effort culminating in an effective GZ action with dynamical mass scale.We briefly review this construction, using the inverse ghost propagator as “diagnostic tool” and we mention some underlying assumptions. A major shortcoming of the original effective action was the incompatibility with BRST invariance. Recent insights allowed to reformulate it into a BRST symmetric version, thereby also opening the road to generalizing the Gribov-Zwanziger approach to other classes of gauges. We pay particular attention to the linear covariant gauge. We also briefly turn to the finite T extension when the Polyakov loop is added to the model via a temporal background gauge field. We discuss and illustrate how previous work (using the GZ original action) is at odds with background gauge invariance, a fact recently remedied as this can be related to the lack of BRST invariance as well. We end by introducing the Nielsen identities and Landau-Khalatnikov-Fradkin (LKF) transformation, which can be used to connect n-point functions in various gauges.We show some (preliminary) results where we used a BRST invariant version of the Serreau-Tissier construction (aka “massive Landau gauge”) to describe a generic linear covariant gauge in relation to lattice gluon data.
