Gravity Amplitudes as Generalized Double Copies

Authors: Zvi Bern, John Joseph Carrasco, Wei-Ming Chen, Henrik Johansson, Radu Roiban

Preprint Number: UUITP-01/17

Whenever a gauge-theory integrand can be arranged into a form where the BCJ duality between color and kinematics is manifest, a corresponding gravity integrand can be obtained directly via the double copy procedure. However, finding such representations at loop level can be challenging. Here we show that we can instead start from generic gauge-theory integrands, where the duality is not manifest, and apply a modified double-copy procedure that incorporates a set of contact terms generated by violations of dual Jacobi identities. We illustrate this with three-, four- and five-loop examples in N = 8 supergravity.