2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/100738Certain perturbative aspects of two-dimensional sigma models with (0,2) supersymmetry are investigated. The main goal is to understand in physical terms how the mathematical theory of ``chiral differential operators'' is related to sigma models. In the process, we obtain, for example, an understanding of the one-loop beta function in terms of holomorphic data. A companion paper will study nonperturbative behavior of these theories.58 pp, minor correctionsHigh Energy Physics - Theorytext