750 GeV Diphotons: Implications for Supersymmetric Unification II

TL;DR

This paper explores supersymmetric models with TeV-scale vector matter multiplets that could explain the 750 GeV diphoton resonance, predicting new particles and signals accessible at the LHC.

Contribution

It identifies six theories with complete SU(5) multiplets that can produce the diphoton signal, detailing how vector matter loops enhance the rate and influence resonance width and discovery prospects.

Findings

Vector matter loops enhance diphoton signal rate.

Resonance width depends on A parameters and phases.

Additional resonances may be observed in future LHC runs.

Abstract

Perturbative supersymmetric gauge coupling unification is possible in six theories where complete SU(5) TeV-scale multiplets of vector matter account for the size of the reported $750~{\rm GeV}$ diphoton resonance, interpreted as a singlet multiplet $S = (s+ia)/\sqrt{2}$. One of these has a full generation of vector matter and a unified gauge coupling $\alpha_G \sim 1$. The diphoton signal rate is enhanced by loops of vector squarks and sleptons, especially when the trilinear $A$ couplings are large. If the $SH_u H_d$ coupling is absent, both $s$ and $a$ can contribute to the resonance, which may then have a large apparent width if the mass splitting from $s$ and $a$ arises from loops of vector matter. The width depends sensitively on $A$ parameters and phases of the vector squark and slepton masses. Vector quarks and/or squarks are expected to be in reach of the LHC. If the $SH_uH_d$ coupling is present, $a$ leads to a narrow diphoton resonance, while a second resonance with decays $s \rightarrow hh, W^+ W^-,ZZ$ is likely to be discovered at future LHC runs. In some of the theories a non-standard origin or running of the soft parameters is required, for example involving conformal hidden sector interactions.