From 100 kpc to 10 Gpc: Dark Matter self-interactions before and after DESI
Cosmology and Nongalactic Astrophysics
2025-07-17 v2 High Energy Physics - Phenomenology
Abstract
We consider Dark Matter self-interactions mediated by ultralight scalars. We show that effectively massless mediators lead to an enhancement of the matter power spectrum, while heavier mediators lead to a suppression, together with a feature around their Jeans scale. We derive the strongest present constraints by combining Planck and BOSS data. The recent DESI measurements of Baryon Acoustic Oscillations exhibit a mild preference for long-range self-interactions, as strong as per mille of the gravitational coupling. Full-shape analyses of forthcoming DESI and Euclid data will confirm or disprove such a hint.
Keywords
Cite
@article{arxiv.2407.18252,
title = {From 100 kpc to 10 Gpc: Dark Matter self-interactions before and after DESI},
author = {Salvatore Bottaro and Emanuele Castorina and Marco Costa and Diego Redigolo and Ennio Salvioni},
journal= {arXiv preprint arXiv:2407.18252},
year = {2025}
}
Comments
5+8 pages, 8 figures; v2: some modifications to the text, all conclusions unchanged. Matches version published in PRD