Gravity amplitudes as generalized double copies of gauge-theory amplitudes

Zvi Bern (1) , John Joseph Carrasco (2) , Wei-Ming Chen (1) , Henrik Johansson (3) , Radu Roiban (4)

1 Department of Physics and Astronomy [UCLA, Los Angeles]
2 IPHT - Institut de Physique Théorique - UMR CNRS 3681
3 Uppsala University
4 Institute for Gravitation and the Cosmos [PennState]

Whenever the integrand of a gauge-theory loop amplitude can be arranged into a form where the BCJ duality between color and kinematics is manifest, a corresponding gravity integrand can be obtained simply via the double-copy procedure. However, finding such gauge-theory representations can be challenging, especially at high loop orders. 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 to obtain gravity integrands that include contact terms generated by violations of dual Jacobi identities. We illustrate this with three-, four- and five-loop examples in $\it N$=8 supergravity.

Mots clés: duality: violation; supergravity: 8; gauge field theory; gravitation; Jacobi identity; kinematics; color

Domaines: Physique [physics]

Zvi Bern, John Joseph Carrasco, Wei-Ming Chen, Henrik Johansson, Radu Roiban. Gravity amplitudes as generalized double copies of gauge-theory amplitudes. Physical Review Letters, 2017, 118, pp.181602. ⟨10.1103/PhysRevLett.118.181602⟩. ⟨cea-01529645v2⟩