Dark Matter with Density-Dependent Interactions

Abstract

The decay and annihilation cross sections of dark matter particles may depend on the value of a chameleonic scalar field that both evolves cosmologically and takes different values depending on the local matter density. This possibility introduces a separation between the physics relevant for freeze-out and that responsible for dynamics and detection in the late universe. We investigate how such dark sector interactions might be implemented in a particle physics Lagrangian and consider how current and upcoming observations and experiments bound such dark matter candidates. A specific simple model allows for an increase in the annihilation cross section by a factor of $10^6$ between freeze-out and today, while more complicated models should also allow for scattering cross sections near the astrophysical bounds.

20 pages; revamped section 6; fixed minor errors and typos; published in PRD

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Cited by in corpus (5)

• Beyond the Cosmological Standard Model
• Warming Nuclear Pasta with Dark Matter: Kinetic and Annihilation Heating of Neutron Star Crusts
• Maximizing Direct Detection with Highly Interactive Particle Relic Dark Matter
• Azimuthal asymmetry in cosmic-ray boosted dark matter flux
• Constraints on new physics around the MeV scale with cosmological observations