One jet to rule them all: monojet constraints and invisible decays of a 750 GeV diphoton resonance

TL;DR

This paper investigates a 750 GeV scalar resonance's production and decay channels, analyzing monojet constraints, potential dark matter candidates, and the compatibility of a broad resonance with collider data.

Contribution

It provides a detailed analysis of monojet constraints on a 750 GeV resonance and explores scenarios reconciling a large width with collider and dark matter constraints.

Findings

Monojet searches exclude much of the parameter space for the resonance.

Certain scenarios allow a broad diphoton resonance to be consistent with monojet constraints.

The stable particle could serve as a dark matter candidate within the model.

Abstract

The ATLAS and CMS collaborations recently reported a mild excess in the diphoton final state pointing to a resonance with a mass of around 750 GeV and a potentially large width. We consider the possibility of a scalar resonance being produced via gluon fusion and decaying to electroweak gauge bosons, jets and pairs of invisible particles, stable at collider scales. We compute limits from monojet searches on such a resonance and test their compatibility with the requirement for a large width. We also study whether the stable particle can be a a dark matter candidate and investigate the corresponding relic density constraints along with the collider limits. We show that monojet searches rule out a large part of the available parameter space and point out scenarios where a broad diphoton resonance can be reconciled with monojet constraints.