Perturbative Analysis of Nonabelian Aharonov-Bohm Scattering
  We perform a perturbative analysis of the nonabelian Aharonov-Bohm problem to one loop in a field theoretic framework, and show the necessity of contact interactions for renormalizability of perturbation theory. Moreover at critical values of the contact interaction strength the theory is finite and preserves classical conformal invariance. 
Dongsu Bak and Oren Bergman