Beta functions in Chirally deformed supersymmetric sigma models in two dimensions

We study two-dimensional sigma models where the chiral deformation diminished the original = (2, 2) supersymmetry to the chiral one, = (0, 2). Such heterotic models were discovered previously on the world sheet of non-Abelian stringy solitons supported by certain four-dimensional = 1 theories. We study geometric aspects and holomorphic properties of these models, and derive a number of exact expressions for the β functions in terms of the anomalous dimensions analogous to the NSVZ β function in four-dimensional Yang-Mills. Instanton calculus provides a straightforward method for the derivation.