Dark Matter Candidates: A Ten-Point Test

TL;DR

This paper proposes a comprehensive ten-point test to evaluate dark matter candidates, integrating relic-density calculations, thermal history, neutrality, BBN and stellar constraints, self-interactions, and direct/indirect observational bounds with experimental discoverability. It synthesizes cosmological (relic density, unitarity limits), astrophysical (BBN, stellar evolution, halo dynamics, gamma rays, neutrinos, antimatter), and experimental (direct detection, collider probes) constraints to map which candidates remain viable. The analysis highlights coannihilations, non-thermal production, and model-specific features (SUSY, UED, axions, sterile neutrinos) that can alter the density and observables, while also stressing that many traditional candidates face stringent, cross-cutting limits. The work provides a practical decision framework for theorists and experimentalists to prioritize models and search strategies, and it emphasizes that discovery potential requires diverse, multi-messenger approaches across cosmology, astrophysics, and collider physics.

Abstract

An extraordinarily rich zoo of non-baryonic Dark Matter candidates has been proposed over the last three decades. Here we present a 10-point test that a new particle has to pass, in order to be considered a viable DM candidate: I.) Does it match the appropriate relic density? II.) Is it {\it cold}? III.) Is it neutral? IV.) Is it consistent with BBN? V.) Does it leave stellar evolution unchanged? VI.) Is it compatible with constraints on self-interactions? VII.) Is it consistent with {\it direct} DM searches? VIII.) Is it compatible with gamma-ray constraints? IX.) Is it compatible with other astrophysical bounds? X.) Can it be probed experimentally?

Figures (9)

• Figure 1: Left: Relic Abundance of $B^{(1)}$ in the UED model as a function of its mass after including no coannihilation (black line), coannihilation with all leptons (blue) and all electroweak particles (red). For the cases with coannihilation, the solid and dashed lines are computed with a mass splitting $\delta = 0.01$ and $0.05$ respectively. Right: The same as in the left panel but accounting for coannihilation of $B^{(1)}$ with all electroweak particles and quarks (blue line), and all level-one KK particles, including KK gluons (red line). Solid and dashed lines are for a mass splitting $\delta = 0.01$ and $0.05$ respectively. From Ref.Burnell.
• Figure 2: Exclusion plot for CHAMPs (solid lines) and NeutralCHAMPs (dotted lines). See text for more details.
• Figure 3: Excluded regions in the mass-charge plane for milli-charged particles. The constraints are relative to: RD plasmon decay in red giants; WD plasmon decay in white dwarfs; BBN big bang Nucleosynthesis; SN Supernova 1987A; AC accelerator experiments; SLAC SLAC millicharged particle search; L Lamb Shift; Op invisible decay of ortho-positronium; DM Dark Matter searches. From Ref. Raffelt Millicharged.
• Figure 4: Excluded regions in the SIMP mass versus SIMP-nucleon cross section plane. The Violet area is excluded by the Earth's heat argument. See Ref.Mack Beacom Bertone SIMP and references therein.
• Figure 5: Upper limits on the spin independent WIMP-nucleon cross section, versus WIMP mass. The blue dashed (points) line is the Ge (Si) CDMS bound CDMS2006. The dark red, pink, green and dark blue curves are the experimental limits respectively from EDELWEISS SI EDELW, CRESST 2004 SI CRESST, ZEPLIN II (Jan. 2007) SI ZEPLIN and WARP SI WARP. The lowest red solid line shows the first results from XENON 10 SI XENON. The red shaded region is the parameter space favored by DAMA experiment Bernabei LargeA. Supersymmetric models allow the filled regions colored: pink SI Baer, green SI Ruiz, dark red SI Baltz and blue SI Baltz Gon. This figure has been obtained with the use of the interface at http://dendera.berkeley.edu/plotter/entryform.html.