A 750 GeV graviton from holographic composite dark sectors

TL;DR

This paper proposes that the 750 GeV di-photon excess could be due to a spin-2 resonance from a strongly interacting dark sector with slight conformality deviation, studied through a holographic 5D model.

Contribution

It introduces a holographic model with a non-AdS warp factor to explain the di-photon excess via a spin-2 resonance from a dark sector, analyzing collider constraints and theoretical bounds.

Findings

The spin-2 resonance can explain the di-photon excess with negligible SM couplings.

Vector resonances around TeV scale are compatible with experimental constraints.

Decoupling vector resonances while explaining the excess is not feasible in the model.

Abstract

We show that the 750 GeV di-photon excess can be interpreted as a spin-2 resonance arising from a strongly interacting dark sector featuring some departure from conformality. This spin-2 resonance has negligible couplings to the SM particles, with the exception of the SM gauge bosons which mediate between the two sectors. We have explicitly studied the collider constraints as well as some theoretical bounds in a holographic five dimensional model with a warp factor that deviates from AdS$_5$. In particular, we have shown that it is not possible to decouple the vector resonances arising from the strong sector while explaining the di-photon anomaly and keeping the five dimensional gravity theory under perturbative control. However, vector resonances with masses around the TeV scale can be present while all experimental constraints are met.