Searching for Signatures of Dark matter-Dark Radiation Interaction in Observations of Large-scale Structure

TL;DR

This study investigates the potential signatures of dark matter-dark radiation interactions in large-scale structure data, finding no significant evidence for such interactions once uncertainties are properly accounted for, and explores model generalizations.

Contribution

The paper critically re-evaluates previous claims of detecting dark matter-dark radiation interactions and extends the model to include different temperature scalings, analyzing their compatibility with observations.

Findings

No significant detection of dark matter-dark radiation interaction when uncertainties are included.

Dark matter-dark radiation model can reconcile Lyα forest data with Planck CMB measurements.

Original interaction scaling with temperature is preferred by current data.

Abstract

In this paper, we conduct a search in the latest large-scale structure measurements for signatures of the dark matter-dark radiation interaction proposed by Buen-Abad et al. (2015). We show that prior claims of a detection of this interaction rely on a use of the SZ cluster mass function that ignores uncertainty in the mass-observable relationship. Including this uncertainty we find that the inferred level of interaction remains consistent with the data, but so does zero interaction; i.e., there is no longer a detection. We also point out that inference of the shape and amplitude of the matter power spectrum from Ly$\alpha$ forest measurements is highly inconsistent with the predictions of the $\Lambda$CDM model conditioned on Planck CMB temperature, polarization, and lensing power spectra, and that the dark matter-dark radiation model can restore that consistency. We also phenomenologically generalize the model of Buen-Abad et al. (2015) to allow for interaction rates with different scalings with temperature, and find that the original scaling is preferred by the data.