Dark Matter Halos as Particle Colliders: Unified Solution to Small-Scale Structure Puzzles from Dwarfs to Clusters

Area of Science:

• Astrophysics
• Cosmology
• Particle Physics

Background:

• Astrophysical observations reveal that dark matter (DM) halos are less dense in their centers than predicted by collisionless DM N-body simulations.
• This discrepancy, known as the core-cusp problem, challenges standard cosmological models.

Purpose of the Study:

• To investigate whether self-interacting dark matter (SIDM) can consistently explain the observed DM halo densities across various astrophysical scales.
• To constrain SIDM model parameters by measuring the dark matter self-interaction cross-section as a function of kinetic energy.

Main Methods:

• Detailed fitting of DM halo properties for galaxies and galaxy clusters.
• Analysis of the velocity dependence of the SIDM cross-section using observational data.
• Comparison of results with theoretical predictions and experimental constraints.

Main Results:

• SIDM provides a consistent solution to the DM deficit problem across dwarf galaxies to galaxy clusters.
• A mildly velocity-dependent cross-section is preferred, ranging from approximately 2 cm²/g on galaxy scales to 0.1 cm²/g on cluster scales.
• Improved constraints on SIDM models are achieved, with potential for measuring dark matter and dark mediator particle masses.

Conclusions:

• Self-interacting dark matter is a viable alternative to collisionless dark matter, resolving the core-cusp problem.
• The measured cross-section provides a direct link to SIDM particle physics, potentially probing hidden dark sectors.
• This research significantly advances our understanding of dark matter properties and its implications for fundamental physics.