Constraints on Dark Matter-Baryon Scattering from the Temperature Evolution of the Intergalactic Medium

TL;DR

This paper uses measurements of the intergalactic medium's temperature evolution to set new constraints on dark matter-baryon scattering cross-sections, particularly at high redshift, providing the first direct limits at z~5.

Contribution

It introduces a novel method to constrain dark matter-baryon interactions using IGM temperature data from the Lyman-alpha forest, especially at high redshift.

Findings

Dark matter-baryon cross-section < 10^{-20} cm^2 for m_χ ≤ 1 GeV

First direct constraint on dark matter-baryon scattering at redshift z~5

IGM temperature evolution effectively probes dark matter interactions

Abstract

The thermal evolution of the intergalactic medium (IGM) can serve as a sensitive probe of cosmological heat sources and sinks. We employ it to limit interactions between dark matter and baryons. After reionization the IGM temperature is set by the balance between photoheating and adiabatic cooling. We use measurements of the IGM temperature from Lyman-$\alpha$-forest data to constrain the cross-section $\sigma$ between dark matter and baryons, finding $\sigma < 10^{-20}$ cm$^2$ for dark-matter masses $m_\chi\leq 1$ GeV. This provides the first direct constraint on scattering between dark matter and baryons at redshift $z\sim5$.