A SUSY Inspired Simplified Model for the 750 GeV Diphoton Excess

TL;DR

This paper proposes a supersymmetry-inspired simplified model to explain the 750 GeV diphoton excess, incorporating new colored scalars and a neutral fermion, consistent with cosmology and testable at the LHC.

Contribution

It introduces a novel simplified model extending the Standard Model with a singlet scalar, colored scalars, and a neutral fermion, linking collider signals with cosmological constraints.

Findings

Model fits the diphoton excess with two parameters

Parameter space constrained by model consistency

Predicts new supersymmetric particles accessible at the LHC

Abstract

The evidence for a new singlet scalar particle from the 750 GeV diphoton excess, and the absence of any other signal of new physics at the LHC so far, suggest the existence of new coloured scalars. To study this possibility, we propose a supersymmetry inspired simplified model, extending the Standard Model with a singlet scalar and with heavy scalar fields carrying both colour and electric charges -- the `squarks'. To allow the latter to decay, and to generate the dark matter of the Universe, we also add a neutral fermion to the particle content. We show that this model provides a two-parameter fit to the observed diphoton excess consistently with cosmology, while the allowed parameter space is bounded by the consistency of the model. In the context of our simplified model this implies the existence of other supersymmetric particles accessible at the LHC, rendering this scenario falsifiable. If this excess persists, it will imply a paradigm shift in assessing supersymmetry breaking and the role of scalars in low scale physics.