New expressions for gravitational scattering amplitudes

Abstract

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. The N=7 recursion is valid for all tree amplitudes, and we illustrate it with a simplified expression for the six-graviton NMHV amplitude. Further new structure emerges when MHV amplitudes are expressed in terms of momentum twistors.

43 pages. Version 2 has a new section 13 with an explanation of why N=7 recursion is valid, plus minor corrections

References in corpus (7)

• Five-Point Amplitudes in N=4 Super-Yang-Mills Theory and N=8 Supergravity
• Eliminating spurious poles from gauge-theoretic amplitudes
• Tree-Level Amplitudes in N=8 Supergravity
• Efficient Tree-Amplitudes in N=4: Automatic BCFW Recursion in Mathematica
• Twistor diagram recursion for all gauge-theoretic tree amplitudes
• Scattering amplitudes for eight gauge fields
• Applications of Subleading-color Amplitudes in N=4 SYM Theory

Cited by in corpus (9)

• Gravity from Rational Curves
• A simple formula for gravitational MHV amplitudes
• Twistor Strings for N=8 Supergravity
• Constructing Amplitudes from Their Soft Limits
• Generating All Tree Amplitudes in N=4 SYM by Inverse Soft Limit
• New Formulae for Gravity Amplitudes: Parity Invariance and Soft Limits
• On Closed Twistor String Theory
• Gravity Amplitudes from n-Space
• Bonus scaling and BCFW in N=7 supergravity