The 750 GeV diphoton resonance as a singlet scalar in an extra dimensional model

TL;DR

This paper proposes interpreting the 750 GeV diphoton excess as a singlet scalar in an extra dimensional model, where loop effects of KK modes of SM fermions enhance couplings to photons and gluons, fitting observed data.

Contribution

It introduces a novel extra dimensional model with a singlet scalar and vector-like fermions to explain the diphoton excess, aligning with LHC observations.

Findings

The model can produce the observed diphoton cross section.

It evades bounds from 8 TeV LHC data.

Enhanced couplings via KK fermion loops are key.

Abstract

We interpret the 750~GeV diphoton excess recently found in the 13~TeV LHC data as a singlet scalar in an extra dimensional model, where one extra dimension is introduced. In the model, the scalar couples to multiple vector-like fermions, which are just the KK modes of SM fermions. Mediated by the loops of these vector-like fermions, the $\phi$ effective couplings to gluons and photons can be significantly large. Therefore, it is quite easy to obtain an observed cross section for the diphoton excess. We also calculate the cross sections for other decay channels of $\phi$, and find that this interpretation can evade the bounds from the 8~TeV LHC data.