750 GeV Di-photon excess at CERN LHC from a dark sector assisted scalar decay

TL;DR

This paper proposes a minimal extension to the Standard Model with a dark sector to explain the 750 GeV diphoton excess observed at CERN LHC, also providing a dark matter candidate.

Contribution

It introduces a dark sector with vector-like leptons aiding a new scalar to decay into diphotons, explaining the excess and addressing dark matter within a unified framework.

Findings

Identifies parameter space consistent with relic density and direct detection constraints.

Demonstrates the scalar decay mechanism explains the 750 GeV diphoton excess.

Provides a viable dark matter candidate from the dark sector.

Abstract

We present a simple extension of the standard model (SM) to explain the diphoton excess, reported by CMS and ATLAS at CERN LHC. The SM is extended by a dark sector including a vector-like lepton doublet and a singlet of zero electromagnetic charge, which are odd under a $Z_2$ symmetry. These vector-like leptons assist the additional scalar, different from SM Higgs, to decay to di-photons of invariant mass around 750 GeV and thus explaining the excess observed at LHC. The admixture of neutral component of the vector-like lepton doublet and singlet constitute the dark matter component of the Universe. We show the relevant parameter space for correct relic density and direct detection of dark matter.