Geometry and beta-functions for N=2 matter models in two dimensions
  We study renormalizable nonlinear sigma-models in two dimensions with N=2 supersymmetry described in superspace in terms of chiral and complex linear superfields. The geometrical structure of the underlying manifold is investigated and the one-loop divergent contribution to the effective action is computed. The condition of vanishing beta-function allows to identify a class of models which satisfy this requirement and possess N=4 supersymmetry. 
Silvia Penati, Andrea Refolli, Alexander Sevrin and Daniela Zanon