[Paper Review] Summarizing experimental sensitivities of collider experiments to dark matter models and comparison to other experiments

A. Boveia, C. Doglioni+20 more|arXiv (Cornell University)|Jun 7, 2022

Dark Matter and Cosmic Phenomena4 citations

TL;DR

This paper summarizes and compares the projected sensitivities of future collider experiments to dark matter models using simplified models, emphasizing complementarity with direct and indirect detection experiments. It demonstrates that collider searches—especially invisible and visible final states—complement other probes, with reach dependent on mediator and dark matter masses, couplings, and mass hierarchies, while also extending these results to light dark sector portal models.

ABSTRACT

Comparisons of the coverage of current and proposed dark matter searches can help us to understand the context in which a discovery of particle dark matter would be made. In some scenarios, a discovery could be reinforced by information from multiple, complementary types of experiments; in others, only one experiment would see a signal, giving only a partial, more ambiguous picture; in still others, no experiment would be sensitive and new approaches would be needed. In this whitepaper, we present an update to a similar study performed for the European Strategy Briefing Book performed within the dark matter at the Energy Frontier (EF10) Snowmass Topical Group We take as a starting point a set of projections for future collider facilities and a method of graphical comparisons routinely performed for LHC DM searches using simplified models recommended by the LHC Dark Matter Working Group and also used for the BSM and dark matter chapters of the European Strategy Briefing Book. These comparisons can also serve as launching point for cross-frontier discussions about dark matter complementarity.

Motivation & Objective

• To assess the sensitivity of future collider experiments to dark matter across various simplified models, focusing on mediator and dark matter masses and couplings.
• To compare collider reach with that of direct and indirect detection experiments, highlighting complementarity and coverage gaps.
• To extend existing collider sensitivity plots to light dark sector portal models, including Higgs and Z-boson portals.
• To provide a framework for cross-experiment comparison and complementarity in dark matter searches, especially for upcoming facilities like FCC-hh and muon colliders.
• To update and expand upon earlier European Strategy Briefing Book plots with new projections from the Snowmass 2021 process.

Proposed method

• Uses simplified dark matter models from the LHC Dark Matter Working Group and the European Strategy Briefing Book as benchmarks.
• Projects future collider sensitivities based on inputs from upcoming facilities, including FCC-hh and muon colliders.
• Applies graphical comparison techniques used in LHC searches, focusing on mono-jet, dijet, and dilepton final states.
• Maps existing LHC simplified models to light dark sector portal models (e.g., dark photon, dark Higgs, axion portals) to enable cross-comparison.
• Recasts existing invisible and visible searches (e.g., mono-jet, Higgs invisible decay) for use in light dark sector models.
• Performs sensitivity comparisons across collider, direct, and indirect detection experiments using consistent parameter spaces and model frameworks.

Experimental results

Research questions

• RQ1 How do future hadron colliders like FCC-hh extend the sensitivity to dark matter models compared to current LHC searches?
• RQ2 What is the relative sensitivity of visible (e.g., dijet, dilepton) versus invisible (e.g., mono-jet) final states in collider searches across different mediator and dark matter masses?
• RQ3 How do collider constraints compare with those from direct and indirect detection experiments in vector and scalar mediator models?
• RQ4 To what extent can existing LHC analyses be recast to probe light dark sector portal models, such as the dark photon or dark Higgs portal?
• RQ5 What role do muon colliders play in probing low- and high-mass dark matter scenarios, especially for minimal WIMP models?

Key findings

• Future hadron colliders such as FCC-hh extend sensitivity to higher mediator and dark matter masses, with reach strongly dependent on the mediator-SM coupling strength.
• For large couplings, searches targeting specific visible final states (e.g., dilepton resonances) dominate sensitivity, while smaller couplings are constrained indirectly.
• Muon colliders operating at center-of-mass energies up to 6 TeV are optimal for probing dark matter candidates below 2 TeV, while higher masses require higher energy and luminosity.
• Invisible searches (e.g., mono-jet) constrain smaller mediator-SM couplings more effectively, leading to stronger limits in the dark matter-nucleon scattering plane.
• Sensitivity to dark matter is highest when the mediator is significantly heavier than the dark matter particle, highlighting the importance of mass ratio in search design.
• Recasting existing LHC searches (e.g., Higgs invisible decay, mono-jet) enables closure of large regions of the relic density benchmark space in light dark sector portal models.