Color-kinematics duality, double copy and the unitarity method for higher-derivative QCD and quadratic gravity

TL;DR

This paper demonstrates that color-kinematics duality extends to higher-derivative QCD-like theories and uses it to efficiently construct quadratic gravity amplitudes via the double-copy method, simplifying complex calculations.

Contribution

It shows the validity of color-kinematics duality for higher-derivative theories and applies the double-copy construction to quadratic gravity, including explicit amplitude computations.

Findings

Color-kinematics duality holds in higher-derivative QCD-like theories.

Double-copy method can be used to construct quadratic gravity amplitudes.

Explicit tree-level and one-loop amplitude calculations support the approach.

Abstract

Here we discuss color-kinematics duality for higher-derivative QCD-like amplitudes. We explicitly show that the duality still holds in this case and it can be instrumental in constructing the associated quadratic-gravity amplitudes by using the double-copy prescription. This allows one to drastically simplify calculations. We also evaluate some tree-level Compton scattering amplitudes in higher-derivative Yang-Mills and quadratic gravity coupled with matter. Furthermore, we illustrate the application of generalized unitarity method for both cases by studying a specific one-loop amplitude.