Two Real Scalar WIMP Model in the Assisted Freeze-Out Scenario

TL;DR

This paper investigates a minimal dark matter model with two interacting scalars, where only one couples to the Higgs, potentially evading direct detection constraints and remaining viable near the Higgs resonance.

Contribution

It introduces a novel two-scalar assisted freeze-out framework with reduced direct detection signals and explores its viability under various theoretical and experimental constraints.

Findings

Model can evade XENON1T constraints in certain parameter regions.

Viable near the Higgs resonance and for scalar masses of hundreds of GeV.

Highly constrained at high energies.

Abstract

We study a simple dark matter model given by two interacting real singlet scalars, with only one of them coupled to the Higgs. The model therefore presents a minimal assisted-freeze-out framework: both scalars contribute to the dark matter relic density, but only one of them takes part in the elastic scattering with nuclei. This reduces the expected interaction rate in direct detection experiments in such a way that the model in some regions of the parameter space may evade XENON1T constraints. We explore the model under theoretical (perturbativity, stability potential and unitarity) and experimental constraints (Higgs to invisible, relic density, direct detection), with the use of the narrow-width-approximation near the Higgs resonance to calculate the average annihilation cross section. We show that the model is viable in the Higgs resonance region and for scalar singlets masses of hundreds of GeV, although the model becomes highly constrained at high energies.