Implications of perturbative unitarity for scalar di-boson resonance searches at LHC

TL;DR

This paper investigates how partial wave unitarity constrains the parameter space of scalar di-boson resonances at the LHC, determining the validity of effective theories and perturbativity bounds for UV completions.

Contribution

It derives unitarity-based limits on the scale of new physics and assesses the feasibility of weakly-coupled models for scalar di-boson signals.

Findings

Unitarity constrains the resonance mass and cross-section combinations.

Perturbativity bounds restrict possible UV completions.

Conditions identified for scalar resonances to be consistent with weak coupling.

Abstract

We study the constraints implied by partial wave unitarity on new physics in the form of spin-zero di-boson resonances at LHC. We derive the scale where the effective description in terms of the SM supplemented by a single resonance is expected to break down depending on the resonance mass and signal cross-section. Likewise, we use unitarity arguments in order to set perturbativity bounds on renormalizable UV completions of the effective description. We finally discuss under which conditions scalar di-boson resonance signals can be accommodated within weakly-coupled models.