Recent observations from weak gravitational lensing (WL) surveys indicate a smoother Universe compared to the predictions of the Cosmic Microwave Background (CMB). This inconsistency is commonly referred to as the σ8 tension or S8 tension, where σ8 represents the present root-mean-square matter fluctuation averaged over a sphere of radius 8h−1Mpc, and S8≡σ8Ωm/0.3. In this article, we investigate a kind of general Dirac-Born-Infeld (DBI) Lagrangian referred to as \textit{surface-type DBI} (sDBI) model. We find that up to the linear order, the constraints on the sDBI model with high-redshift probe (CMB) and low-redshift probes (WL and Galaxy Clustering, GC) yield S8=0.7448−0.21+0.031 and 0.7426−0.085+0.054, respectively. Remarkably, these values not only demonstrate self-consistency but also align with the values obtained from the majority of low-redshift probes. Furthermore, we present a discussion on exploring the non-linear effects of this model, which holds the potential to address additional challenges associated with Cold Dark Matter (CDM) on small scales.
@article{arxiv.2307.04394,
title = {Relieving the $S_8$ Tension: Exploring the Surface-type DBI Model as a Dark Matter Paradigm},
author = {Xingpao Suo and Xi Kang and Huanyuan Shan},
journal= {arXiv preprint arXiv:2307.04394},
year = {2023}
}