Heterotic non-linear sigma models with anti-de Sitter target spaces Original Research Article

We calculate the beta function of non-linear sigma models with image and image target spaces in a image expansion up to order image and to all orders in image. This beta function encodes partial information about the spacetime effective action for the heterotic string to all orders in image. We argue that a zero of the beta function, corresponding to a worldsheet CFT with image target space, arises from competition between the one-loop and higher-loop terms, similarly to the bosonic and supersymmetric cases studied previously in [J.J. Friess, S.S. Gubser, Non-linear sigma models with anti-de Sitter target spaces, Nucl. Phys. B 750 (2006) 111–141]. Various critical exponents of the non-linear sigma model are calculated, and checks of the calculation are presented.