# Two-Loop Beta Functions Without Feynman Diagrams

Research paper by Peter E. Haagensen, Kasper Olsen, Ricardo Schiappa

Indexed on: 10 Sep '97Published on: 10 Sep '97Published in: High Energy Physics - Theory

#### Abstract

Starting from a consistency requirement between T-duality symmetry and renormalization group flows, the two-loop metric beta function is found for a d=2 bosonic sigma model on a generic, torsionless background. The result is obtained without Feynman diagram calculations, and represents further evidence that duality symmetry severely constrains renormalization flows.