Grassmannian heterotic sigma model

We study the nonminimal supersymmetric heterotically deformed N=(0,2) sigma model with the Grassmannian target space GM,N. To develop the appropriate superfield formalism, we begin with a simplified model with flat target space, find its beta function up to two loops, and prove a nonrenormalization theorem. Then we generalize the results to the full model with the Grassmannian target space. Using the geometric formulation, we calculate the beta functions and discuss the 't Hooft and Veneziano limits.