On-Shell Perspectives on the Massless Limit of Massive Supergravity

TL;DR

This paper explores the massless limit of massive supergravity using on-shell methods, revealing a discontinuity similar to the vDVZ effect in massive gravity, and offers new insights into its underlying structure.

Contribution

It applies on-shell techniques to analyze the massless limit of massive supergravity, providing a novel perspective on the Deser-Kay-Stelle discontinuity.

Findings

Identifies a discontinuity in the massless limit of massive supergravity

Uses on-shell methods to analyze supergravity amplitudes

Provides a new understanding of the Deser-Kay-Stelle discontinuity

Abstract

Massive gravity exhibits a famous discontinuity in its 2-point linearized amplitude for t-channel scattering of gravitational sources, in the $m \to 0$ limit. In essence, the source of this vDVZ discontinuity is in the failure of the zero-helicity mode to decouple in this limit. In [1], we showed how this result could be understood in the context of modern on-shell methods and, in particular, the BCFW construction. In this article, we provide a similar on-shell perspective to the equally interesting but lesser known discontinuity first discovered by Deser, Kay and Stelle in massive supergravity.