Self-Interacting Dark Matter
Despite its veiled nature, dark matter is considered the main driver of structure formation in the Universe. The current paradigm, the cosmological constant plus cold dark matter (ΛCDM) cosmological model, has been successful in describing the large scale structures in the Universe. However, in recent decades, evidence from astrophysical observations on small-scale (∼ kpc) structures and absence of signal from particle physics experiments have motivated conjectures on alternative dark matter models.
Self-interacting dark matter (SIDM) is an important category of alternative dark matter models (or in general hidden-sector models for beyond-standard-model physics) that has been proposed and discussed in the literature for about three decades. The introduction of SIDM could potentially solve some small-scale problems (see the review by Tulin Sean and Yu Hai-Bo).
