Could the width of the diphoton anomaly signal a three-body decay ?

TL;DR

The paper proposes that the broad diphoton anomaly at the LHC could be explained by three-body decays involving an extra state, offering a new interpretation that aligns with existing search constraints.

Contribution

It introduces the idea that three-body decay processes can produce broad diphoton signals, providing a novel explanation for the observed anomaly.

Findings

Three-body decay processes can produce broad diphoton signals.

This interpretation fits the observed anomaly better than a simple resonance.

It offers new avenues for constructing models of New Physics.

Abstract

The recently observed diphoton anomaly at the LHC appears to suggest the presence of a rather broad resonance. In this note, it is pointed out that this does not hold if the two photons are produced along with an extra state. Specifically, the diphoton invariant mass arising from various $A \to B\gamma\gamma$ processes, with $A,B$ being scalars, fermions, or vectors, though peaked at a rather large value, would naturally be broad and could fit rather well the observed deviations. This interpretation has a number of advantages over the two-photon resonance hypothesis, for example with respect to the compatibility with the 8 TeV diphoton, dilepton or dijet searches, and opens many new routes for New Physics model construction.