Direct signals from electroweak singlets through the Higgs portal

TL;DR

This paper reviews the detection prospects and constraints for Higgs portal dark matter, highlighting the mass ranges testable by upcoming direct detection experiments and the limitations for certain fermionic models.

Contribution

It provides a comprehensive analysis of Higgs portal dark matter detection prospects across different models and mass ranges, including experimental constraints and future sensitivities.

Findings

Resonance region near half the Higgs mass is testable by XENONnT and LZ.

Full mass range up to unitarity limit can be explored by DarkSide-20k and DARWIN.

Fermionic models with pure CP odd coupling are difficult to test with upcoming experiments.

Abstract

We review predictions and constraints for nuclear recoil signals from Higgs portal dark matter under the assumption of standard thermal creation from freeze-out. Thermally created scalar and vector Higgs portal dark matter masses are constrained to be in the resonance region near half the Higgs mass or above several TeV. The resonance region for these models will be tested by XENONnT and LZ. The full mass range up to the unitarity limit can be tested by DarkSide-20k and DARWIN. Fermionic Higgs portal dark matter with a pure CP odd coupling is constrained by the Higgs decay width, but has strongly suppressed recoil cross sections which cannot be tested with upcoming experiments. Fermionic Higgs portal dark matter with a combination of CP even and odd Higgs couplings can be constrained by the direct search experiments.