Nagoya University
Theoretical Elementary Particle Physics Laboratory

Date&Time Tue Oct 18 2022 (17:00 - 18:00)
David Dudal
Affiliation KU Leuven
Title Looking beyond the Landau gauge Gribov horizon
Abstract 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 (G) himself at leading order, and improved upon to all orders by Zwanziger (Z), an effort culminating in an effective GZ action with a non-perturbative 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. We discuss how to reformulate it into a BRST symmetric version, thereby also opening the road to generalizing the GZ approach to other gauges. We pay particular attention to the linear covariant gauge. We also briefly turn to the finite temperature extension when the Polyakov loop is added to the model via a temporal background gauge field, where we focus on both BRST and background gauge invariance. 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 use a BRST invariant version of the Serreau-Tissier construction (aka “massive Landau gauge”).