Speaker
Description
In this talk, we report on new results for SU(N) Yang-Mills theory in
four dimensions in the continuum formulation. Using the background
field method, we find that the notorious infrared divergences of the
effective action cancel between gauge and matter sectors for QCD if
the number of massless quark flavors is exactly Nf = 4N, but not if
Nf=0. Improving the calculation for pure Yang-Mills by including
fluctuations around the background field, we use well-developed
techniques to go beyond one-loop order to calculate non-perturbative
contributions from the quartic interactions. It has been claimed by
Savvidy and others that non-perturbative contributions from quartic
interactions will regulate the IR divergences found in one-loop
calculations of the Yang-Mills vacuum, potentially making it possible
to calculate the Yang-Mills mass gap. We report on the status of this
claim in this talk.
