Simplifying amplitudes in Maxwell-Einstein and Yang-Mills-Einstein supergravities

TL;DR

This work surveys double-copy constructions for $N=2$ supergravities in four and five dimensions, focusing on Maxwell-Einstein and Yang-Mills-Einstein theories. It shows gravity amplitudes can be obtained as bilinear combinations of gauge-theory amplitudes when color/kinematics duality is realized on at least one factor, using a pair of theories: pure $N=2$ sYM and a dimensionally reduced YM-scalar. The analysis covers isometry gaugings, spontaneous symmetry breaking, and homogeneous target spaces, reproducing the generic Jordan family and magical theories and extending to Higgsed and hypermultiplet-containing cases. Together these results pave the way for loop-level explorations and deepen the understanding of how reduced-supersymmetry gravity relates to gauge theories via the double copy.

Abstract

This article reviews recent progress in formulating double-copy constructions for scattering amplitudes in supergravity theories with N=2 supersymmetry in five and four spacetime dimensions. Particular attention is devoted to infinite families of Maxwell-Einstein theories with symmetric and homogeneous target spaces and to Yang-Mills-Einstein theories with compact gauge groups. Extension of the construction to theories with spontaneously-broken gauge symmetry is also discussed.