The 3-loop Beta Function of QCD
  Using the background field technique, we calculate the 3-loop beta function of lattice $SU(N)$ gauge theories. In the pure gluonic case, we present our results, comparing to those recently obtained by Luescher and Weisz. We also provide a progress report in the case of QCD with Wilson fermions. 
B. Alles, C. Christou, A. Feo, H. Panagopoulos, E. Vicari