Probing Higgs-portal dark matter with vector-boson fusion

TL;DR

This paper constrains Higgs-portal dark matter models using vector-boson fusion data from the LHC, providing limits on the coupling and dark-matter mass, especially near the Higgs resonance, and projecting future collider sensitivities.

Contribution

It introduces a detailed analysis of Higgs-portal dark matter constraints near the Higgs resonance, including systematic uncertainties and future collider projections.

Findings

Current limits constrain dark-matter masses up to 110 GeV.

Higgs invisible branching ratio limits reach 2%.

Projections show improved sensitivity at HL-LHC and HE-LHC.

Abstract

We constrain the Higgs-portal model employing the vector-boson fusion channel at the LHC. In particular, we include the phenomenologically interesting parameter region near the Higgs resonance, where the Higgs-boson mass is close to the threshold for dark-matter production and a running-width prescription has to be employed for the Higgs-boson propagator. Limits for the Higgs-portal coupling as a function of the dark-matter mass are derived from the CMS search for invisible Higgs-boson decays in vector-boson fusion at 13 TeV. Furthermore, we perform projections for the 14 TeV HL-LHC and the 27 TeV HE-LHC taking into account a realistic estimate of the systematic uncertainties. The respective upper limits on the invisible branching ratio of the Higgs boson reach a level of 2 % and constrain perturbative Higgs-portal couplings up to dark-matter masses of about 110 GeV.