One-loop unifying relations between Yang-Mills theory and the nonlinear sigma model from Berends-Giele currents
The paper explores unifying relations between Yang-Mills theory and nonlinear sigma models by extending tree-level amplitude rules to one-loop integrands. It achieves this by using Berends–Giele currents and sewing off-shell tree-level objects. The method verifies that one-loop Yang–Mills diagrams map directly onto nonlinear sigma model diagrams, providing a concrete link between the two theories.