  We explain how the lowest-order classical gravitational radiation produced
during the inelastic scattering of two Schwarzschild black holes in General
Relativity can be obtained from a tree scattering amplitude in gauge theory
coupled to scalar fields. The gauge calculation is related to gravity through
the double copy. We remove unwanted scalar forces which can occur in the double
copy by introducing a massless scalar in the gauge theory, which is treated as
a ghost in the link to gravity. We hope these methods are a step towards a
direct application of the double copy at higher orders in classical
perturbation theory, with the potential to greatly streamline gravity
calculations for phenomenological applications.

High Energy Physics - Theory;General Relativity and Quantum Cosmology;High Energy Physics - Phenomenology