PREPRINT
1F2420D1-ABAC-437A-987B-B484CD77EA2D

# Full-shape BOSS constraints on dark matter interacting with dark radiation and lifting the ${S}_{8}$ tension

Henrique Rubira, Asmaa Mazoun, Mathias Garny
arXiv:2209.03974

Submitted on 8 September 2022

## Abstract

In this work we derive constraints on interacting dark matter-dark radiation models from a full-shape analysis of BOSS-DR12 galaxy clustering data, combined with Planck legacy cosmic microwave background (CMB) and baryon acoustic oscillation (BAO) measurements. We consider a set of models parameterized within the effective theory of structure formation (ETHOS), quantifying the lifting of the ${S}_{8}$ tension in view of KiDS weak-lensing results. The most favorable scenarios point to a fraction $f\sim 10-100\mathrm{%}$ of interacting dark matter as well as a dark radiation temperature that is smaller by a factor $\xi \sim 0.1-0.15$ compared to the CMB, leading to a reduction of the tension to the $\sim 1\sigma$ level. The temperature dependence of the interaction rate favored by relaxing the ${S}_{8}$ tension is realized for a weakly coupled unbroken non-Abelian $SU\left(N\right)$ gauge interaction in the dark sector. To map our results onto this $SU\left(N\right)$ model, we compute higher-order corrections due to Debye screening. We find a lower bound ${\alpha }_{d}\equiv {g}_{d}^{2}/\left(4\pi \right)\gtrsim {10}^{-8}\left({10}^{-9}\right)$ for dark matter mass $1000\left(1\right)$ GeV for relaxing the ${S}_{8}$ tension, consistent with upper bounds from galaxy ellipticities and compatible with self-interactions relevant for small-scale structure formation.

## Preprint

Comment: 38 pages, 8 figures, 1 ancillary figure

Subjects: Astrophysics - Cosmology and Nongalactic Astrophysics; High Energy Physics - Phenomenology