Note on Soft Graviton theorem by KLT Relation

TL;DR

This paper explores the soft graviton theorem using KLT relations, linking Yang-Mills amplitudes to gravity amplitudes and revealing new identities in the KLT momentum kernel.

Contribution

It demonstrates how the soft behavior of Yang-Mills amplitudes translates to gravity amplitudes via KLT relations, uncovering new identities in the process.

Findings

Soft behavior of gravity amplitudes derived from Yang-Mills amplitudes.

Discovery of two nontrivial identities of the KLT momentum kernel.

Abstract

Recently, new soft graviton theorem proposed by Cachazo and Strominger has inspired a lot of works. In this note, we use the KLT-formula to investigate the theorem. We have shown how the soft behavior of color ordered Yang-Mills amplitudes can be combined with KLT relation to give the soft behavior of gravity amplitudes. As a byproduct, we find two nontrivial identities of the KLT momentum kernel must hold.