LHC-friendly freeze-in dark matter via Higgs portal

TL;DR

This paper proposes a two-field Higgs portal freeze-in dark matter model where a scalar mediator, detectable at HL-LHC, enables indirect inference of dark matter properties despite lack of direct detection signals.

Contribution

It introduces a novel two-field freeze-in dark matter model with a scalar mediator accessible at colliders, expanding detection prospects beyond single-field scenarios.

Findings

Scalar mediator detectable via HL-LHC channels.

Allowed scalar mass window of 10-50 GeV.

Derived exclusion and discovery limits based on improved cuts.

Abstract

It is known that single-field freeze-in dark matter barely leaves footprints in dark matter direct detection and collider experiments. This situation can be altered in two-field context. In this work we propose a two-field freeze-in dark matter model through Higgs portal. The observed dark matter relic abundance is obtained by a decay of scalar mediator thermalized in the early Universe. While there is a lack of direct dark matter signals, the scalar mediator is in the reach of HL-LHC either through vector boson fusion or Mono-Z channel. Within allowed scalar mass window of 10-50 GeV, we use improved cuts to derive both $2\sigma$ exclusion and $5\sigma$ discovery limits, depending on the value of Higgs portal coupling. If verified, this scalar mediator signal allows us to infer the freeze-in dark matter.