New expressions for gravitational scattering amplitudes
New methods are introduced for evaluating tree-level gravitational scattering amplitudes. A new N=7 super-symmetric recursion yields amplitudes free from the spurious double poles of the N=8 theory. This is illustrated by a new nine-term expression for the six-graviton NMHV amplitude. The general scheme also implies a simplified recurrence relation for MHV amplitudes. We show how this relation is satisfied by a new expression for MHV amplitudes, far simpler than those hitherto identified, and exhibiting manifest Sn symmetry. This reformulation is related to a new momentum-twistor representation of the MHV amplitudes.
KeywordsSupersymmetric gauge theory Scattering Amplitudes
- N. Arkani-Hamed, personal communication.Google Scholar
- N. Arkani-Hamed, Scattering without space-time, presentation given at the RP80 Oxford conference Twistors, Geometry and Physics, Oxford, U.K., 21–22 July 2011 http://people.maths.ox.ac.uk/lmason/RP80/nima.pdf.
- R. Penrose, Twistor theory, its aims and achievements, in Quantum Gravity, C.J. Isham, R. Penrose and D.W. Sciama eds., Oxford University Press, Oxford, U.K. (1975).Google Scholar
- Y.t. Huang, private communication (2011).Google Scholar