750 GeV Diphotons: Implications for Supersymmetric Unification

TL;DR

This paper explores how a 750 GeV diphoton signal at the LHC can be explained within supersymmetric unification models involving vector quarks and leptons, constraining their masses and interactions through renormalization group analysis.

Contribution

It provides a comprehensive analysis of theories with vector quarks and leptons that achieve gauge coupling unification and explains the diphoton resonance with precise predictions for particle masses and widths.

Findings

Vector quarks and leptons must be light, typically 375 GeV to 700 GeV.

Yukawa couplings flow to specific TeV-scale values, independent of UV physics.

The resonance width can be less than experimental resolution or about tens of GeV due to loop effects.

Abstract

A recent signal of 750 GeV diphotons at the LHC can be explained within the framework of supersymmetric unification by the introduction of vector quarks and leptons with Yukawa couplings to a singlet S that describes the 750 GeV resonance. We study the most general set of theories that allow successful gauge coupling unification, and find that these Yukawa couplings are severely constrained by renormalization group behavior: they are independent of ultraviolet physics and flow to values at the TeV scale that we calculate precisely. As a consequence the vector quarks and leptons must be light; typically in the region of 375 GeV to 700 GeV, and in certain cases up to 1 TeV. The 750 GeV resonance may have a width less than the experimental resolution; alternatively, with the mass splitting between scalar and pseudoscalar components of S arising from one-loop diagrams involving vector fermions, we compute an apparent width of 10s of GeV.