Non-holomorphic effective potential in N = 4 SU(n) SYM
  We compute the one-loop non-holomorphic effective potential for the N=4 SU(n) supersymmetric Yang-Mills theory with the gauge symmetry broken down to the maximal torus. Our approach remains powerful for arbitrary gauge groups and is based on the use of N=2 harmonic superspace formulation for general N=2 Yang-Mills theories along with the superfield background field method. 
E. I. Buchbinder, I. L. Buchbinder and S. M. Kuzenko