On-Shell Recursion Relations for Generic Theories

TL;DR

This paper demonstrates that on-shell recursion relations are valid for tree-level amplitudes in a wide range of two-derivative theories with multiple particle types and spins, including gauge theories and supergravity.

Contribution

It establishes the applicability of on-shell recursion relations to generic two-derivative theories with diverse particles, extending previous results to broader classes of models.

Findings

Recursion relations hold for amplitudes with at least one gluon or graviton.

Valid for theories like QCD, N=4 SYM, and N=8 supergravity.

Applicable to tree amplitudes in theories with scalars, fermions, and gauge fields.

Abstract

We show that on-shell recursion relations hold for tree amplitudes in generic two derivative theories of multiple particle species and diverse spins. For example, in a gauge theory coupled to scalars and fermions, any amplitude with at least one gluon obeys a recursion relation. In (super)gravity coupled to scalars and fermions, the same holds for any amplitude with at least one graviton. This result pertains to a broad class of theories, including QCD, N=4 SYM, and N=8 supergravity.