Determination of Dark Matter Properties at High-Energy Colliders

TL;DR

The paper assesses how next-generation colliders, especially the ILC, can determine the microscopic properties of WIMP dark matter within MSSM neutralino scenarios. By analyzing four benchmark points with a 24-parameter MSSM framework and using Markov Chain Monte Carlo, the authors quantify how collider data constrain Ωχh^2, ⟨σv⟩, and σχp, and how these feed into interpretations of gamma-ray, direct-detection, and halo-structure observations. They find that LHC data provide partial constraints, while ILC data—particularly at 1000 GeV—substantially sharpen predictions and can distinguish competing neutralino compositions, approaching Planck-level relic-density precision in favorable cases. The work demonstrates a powerful, synergistic framework where collider measurements inform astrophysical analyses, enabling tests of whether the collider-observed particle is the dominant component of cosmic dark matter and guiding our understanding of dark matter distribution in the galaxy.

Abstract

If the cosmic dark matter consists of weakly-interacting massive particles, these particles should be produced in reactions at the next generation of high-energy accelerators. Measurements at these accelerators can then be used to determine the microscopic properties of the dark matter. From this, we can predict the cosmic density, the annihilation cross sections, and the cross sections relevant to direct detection. In this paper, we present studies in supersymmetry models with neutralino dark matter that give quantitative estimates of the accuracy that can be expected. We show that these are well matched to the requirements of anticipated astrophysical observations of dark matter. The capabilities of the proposed International Linear Collider (ILC) are expected to play a particularly important role in this study.

Figures (62)

• Figure 1: Contours in a parameter space of supersymmetry models for the discovery of the missing energy plus jets signature of new physics by the ATLAS experiment at the LHC. The three sets of contours correspond to levels of integrated luminosity at the LHC (in fb$^{-1}$), contours of constant squark mass, and contours of constant gluino mass. From Tovey.
• Figure 2: Four scenarios for decay chains observed at LHC. Each exhibits jets, hard leptons, and missing energy. Distinguishing between these cases by detailed study of energy distributions may not be possible with LHC alone.
• Figure 3: Threshold behavior of pair production cross sections for spin 1/2 (KK muon) and spin 0 (smuon) counterpart to the Standard Model muon. These distributions are easily distinguished by an $e^+e^-$ collider.
• Figure 4: Projected significance contours ($1,2,3,4 \sigma$) in the plane of WIMP mass versus cross section for an observation of dark matter by the SuperCDMS experiment (25 kg target, two year dataset) superCDMSSchnee, compared to the determination of these parameters from data from the LHC. The projections are done using the model LCC3, to be defined in Section 3.2.
• Figure 5: (a) Suggested profiles of the dark matter mass density near the galactic center NFWMoore. (b) Corresponding values of $\left\langle{ J} \right\rangle$ at the galactic center, as a function of the angular resolution indicated as a circle size in sr.