It is a Graviton! or maybe not

TL;DR

This paper investigates how to differentiate Kaluza-Klein gravitons from impostor spin-two resonances, showing they couple similarly to the Standard Model but can be distinguished by their decay ratios, revealing limits of duality.

Contribution

It proves that both KK gravitons and impostors couple via the same dimension-five operators, and proposes using decay ratios to distinguish them.

Findings

KK gravitons and impostors couple through the same operators

Decay ratio analysis can differentiate KK gravitons from impostors

The duality between AdS and strongly-coupled theories can break down

Abstract

The discovery of Kaluza-Klein (KK) gravitons is a smoking gun of extra dimensions. Other scenarios, however, could give rise to spin-two resonances of a new strongly-coupled sector and act as impostors. In this paper we prove that a spin-two resonance does not couple to the Standard Model through dimension-four operators. We then show that the massive graviton and its impostor both couple to the Standard Model through the same dimension-five operators. Therefore the spin determination is identical. Nevertheless, we also show that one can use the ratio of branching ratios to photons and to jets for distinguishing between KK gravitons and their impostors. The capacity to distinguish between KK gravitons and impostors is a manifestation of the breakdown of the duality between AdS and strongly-coupled theories.