The Higgs Portal Above Threshold

TL;DR

This paper investigates collider signatures of heavy singlet scalars produced via the Higgs Portal at 14 TeV and 100 TeV colliders, focusing on off-shell Higgs production and potential signals like missing energy and monojet events.

Contribution

It provides a systematic analysis of collider signatures for heavy Higgs Portal scalars, especially in the off-shell production regime, and forecasts sensitivities at future colliders.

Findings

Collider searches can probe significant regions of Higgs Portal parameter space.

Off-shell Higgs production channels are promising for detecting heavy scalars.

Future colliders greatly extend the reach for singlet scalars related to dark matter and baryogenesis.

Abstract

The discovery of the Higgs boson opens the door to new physics interacting via the Higgs Portal, including motivated scenarios relating to baryogenesis, dark matter, and electroweak naturalness. We systematically explore the collider signatures of singlet scalars produced via the Higgs Portal at the 14 TeV LHC and a prospective 100 TeV hadron collider. We focus on the challenging regime where the scalars are too heavy to be produced in the decays of an on-shell Higgs boson, and instead are produced primarily via an off-shell Higgs. Assuming these scalars escape the detector, promising channels include missing energy in association with vector boson fusion, monojets, and top pairs. We forecast the sensitivity of searches in these channels at $\sqrt{s} = 14$ & 100 TeV and compare collider reach to the motivated parameter space of singlet-assisted electroweak baryogenesis, Higgs Portal dark matter, and neutral naturalness.