KLT and New Relations for N=8 SUGRA and N=4 SYM

TL;DR

This paper proves supersymmetric KLT relations linking N=8 supergravity and N=4 super Yang-Mills amplitudes at tree level, unifying previous relations and revealing new amplitude identities without relying on string theory or Lagrangians.

Contribution

It establishes supersymmetric KLT relations purely within the S-matrix framework, unifying and extending known amplitude relations in gauge and gravity theories.

Findings

Unified supersymmetric KLT relations for N=8 SUGRA and N=4 SYM

Derived new identities for amplitudes with scalars and fermions

Reduced helicity basis size using new amplitude identities

Abstract

In this short note, we prove the supersymmetric Kawai-Lewellen-Tye (KLT) relations between N=8 supergravity (SUGRA) and N=4 super Yang-Mills (SYM) tree-level amplitudes in the frame of S-matrix program, especially we do not use string theory or the explicit Lagrangian form of corresponding theories. Our supersymmetric KLT relations naturally unify the non-supersymmetric KLT relations and newly discovered gauge theory identities and produce more identities for amplitudes involving scalars and fermions. We point out also that these newly discovered identities can be used to reduce helicity basis from (n-3)! further down.