Interpretation of 750 GeV Diphoton Excess at LHC in Singlet Extension of Color-octet Neutrino Mass Model

TL;DR

This paper explains the 750 GeV diphoton excess observed at the LHC using an extended color-octet neutrino mass model with a scalar singlet, highlighting how scalar and fermion loops enhance the diphoton rate.

Contribution

It introduces a novel extension of the color-octet neutrino mass model with a scalar singlet to account for the diphoton excess, demonstrating compatibility with LHC constraints.

Findings

Diphoton cross section can reach 3-10 fb with TeV-scale particles.

Interference between scalar and fermion loops enhances the diphoton rate.

Model evades current LHC limits while explaining the excess.

Abstract

We propose that the possible 750 GeV diphoton excess can be explained in the color-octet neutrino mass model extended with a scalar singlet $\Phi$. The model generally contains $N_s$ species of color-octet, electroweak doublet scalars $S$ and $N_f$ species of color-octet, electroweak triplet $\chi$ or singlet $\rho$ fermions. While both scalars and fermions contribute to the production of $\Phi$ through gluon fusion, only the charged members induce the diphoton decay of $\Phi$. The diphoton rate can be significantly enhanced due to interference between the scalar and fermion loops. We show that the diphoton cross section can be from 3 to 10 fb for O(TeV) color-octet particles while evading all current LHC limits.