New expressions for gravitational scattering amplitudes

Understand

New methods are introduced for the description and evaluation of tree-level gravitational scattering amplitudes.

• An N=7 super-symmetric recursion, free from spurious double poles, gives a more efficient method for evaluating MHV amplitudes.
• The recursion is naturally associated with twistor geometry, and thereby gives a new interpretation for the amplitudes.
• The recursion leads to new expressions for the MHV amplitudes for six and seven gravitons, simplifying their symmetry properties, and suggesting further generalization.