Neutralino Dark Matter at 14 and 100 TeV

TL;DR

This work assesses the potential of a 100 TeV proton-proton collider to probe TeV-scale neutralino dark matter within supersymmetric simplified models. It analyzes monojet, soft-lepton, and disappearing-track channels across pure, compressed, and coannihilating spectra, comparing to 14 TeV LHC projections. The study finds a broad 4–5× enhancement in mass reach, with exclusive sensitivity to multi-TeV winos and higgsinos, and substantial coverage of coannihilating scenarios such as gluino, stop, and squark coannihilation. The results underscore the importance of high-energy collider reaches for thermally viable dark matter and highlight the role of detector-systematic assumptions in shaping future discovery potential.

Abstract

In recent years the search for dark matter has intensified with competitive bounds coming from collider searches, direct detection, and indirect detection. Collider searches at the Large Hadron Collider (LHC) lack the necessary center-of-mass energy to probe TeV-scale dark matter. It is TeV-scale dark matter, however, that remains viable for many models of supersymmetry. In this paper, we study the reach of a 100 TeV proton-proton collider for neutralino dark matter and compare to 14 TeV LHC projections. We employ a supersymmetric simplified model approach and present reach estimates from monojet searches, soft lepton searches, and disappearing track searches. The searches are applied to pure neutralino spectra, compressed neutralino spectra, and coannihilating spectra. We find a factor of 4-5 improvement in mass reach in going from 14 TeV to 100 TeV. More specifically, we find that given a 1% systematic uncertainty, a 100 TeV collider could exclude winos up to 1.4 TeV and higgsinos up to 850 GeV in the monojet channel. Coannihilation scenarios with gluinos can be excluded with neutralino masses of 6.2 TeV, with stops at 2.8 TeV, and with squarks at 4.0 TeV. Using a soft lepton search, compressed spectra with a chargino-neutralino splitting of $Δm = 20 - 30$ GeV can exclude neutralinos at $\sim$ 1 TeV. Given a sufficiently long chargino lifetime, the disappearing track search is very effective and we extrapolate current experimental bounds to estimate that a $\sim$ 2 TeV wino could be discovered and a $\sim$ 3 TeV wino could be excluded.

Figures (14)

• Figure 1: The mass reach in the pure wino scenario in the monojet channel with $\mathcal{L}=3000~\mathrm{fb}^{-1}$ for the $14~\mathrm{TeV}$ LHC (blue) and a $100~\mathrm{TeV}$ proton-proton collider (red). The bands are generated by varying the background systematics between $1-2 \%$ and the signal systematic uncertainty is set to $10 \%$.
• Figure 2: Chargino track distributions for the pure wino scenario showing the number of tracks for a given track length (left) and the number of tracks for a given wino mass (right). Only events passing the analysis cuts in App. \ref{['app:analysis']} and containing at least one chargino track with $p_T>500~\mathrm{GeV}$ are considered.
• Figure 3:
• Figure 4: The mass reach in the pure higgsino scenario in the monojet channel with $\mathcal{L}=3000~\mathrm{fb}^{-1}$ for the $14~\mathrm{TeV}$ LHC (blue) and a $100~\mathrm{TeV}$ proton-proton collider (red). The bands are generated by varying the background systematics between $1-2 \%$ and the signal systematic uncertainty is set to $10 \%$.
• Figure 5: Chargino track distributions for the pure higgsino scenario showing the number of tracks for a given track length (left) and the number of tracks for a given higgsino mass (right). The dashed lines shows the same plots with a neutralino-chargino mass splitting half the standard value, and the dashed-dotted lines show the same plots with a neutralino-chargino mass splitting twice the standard value. Only events passing the analysis cuts in App. \ref{['app:analysis']} and containing at least one chargino track with $p_T>500~\mathrm{GeV}$ are considered.