$n$-point amplitudes with a single negative-helicity graviton

TL;DR

This paper derives a new formula for one-loop graviton scattering amplitudes with one negative-helicity graviton, revealing enhanced soft-limit behavior beyond previous conjectures.

Contribution

It introduces an augmented recursion method to compute n-point one-loop graviton amplitudes with a single negative helicity, advancing computational techniques in quantum gravity.

Findings

Derived explicit expression for the amplitude

Demonstrated non-universal soft-limit behavior

Enhanced understanding of soft graviton dynamics

Abstract

We construct an expression for the n-point one-loop graviton scattering amplitude with a single negative helicity external leg using an augmented recursion technique. We analyse the soft-limits of these amplitudes and demonstrate that they have soft behaviour beyond the conjectured universal behaviour.