The massive gluon and the massless pion
2020 May 06
2020 May 26
Lattice simulations of Yang-Mills theories and QCD in the Landau gauge demonstrate that the gluon propagator reaches a finite nonzero value at vanishing momentum. This can be modelled by a simple deformation of the corresponding Faddeev-Popov Lagrangian known as the Curci-Ferrari model. The latter does not modify the known ultraviolet regime of the theory and provides a successful perturbative description of essential aspects of the non-Abelian dynamics in the infrared regime, where, in particular, the coupling remains finite, as also seen in lattice simulations. This opens the possibility of a controlled (semi)perturbative description of various aspects of the infrared QCD dynamics, including correlation functions and the deconfinement phase transition at finite temperature and density. I present recent progress concerning the description of chiral symmetry breaking in this context.