Revisiting CMB constraints on dark matter annihilation

TL;DR

This paper refines constraints on dark matter annihilation by updating ionization history simulations with helium interactions, using Planck 2018 data to improve the precision of the bounds.

Contribution

It introduces an improved simulation code for ionization history that includes helium effects, providing more accurate CMB constraints on dark matter properties.

Findings

Updated constraints on dark matter annihilation cross section

Enhanced simulation accuracy with helium interactions

Refined bounds using Planck 2018 data

Abstract

The precision measurements of the cosmic microwave background power spectrum put a strong constraint on the dark matter annihilation cross section since the electromagnetic energy injection by the dark matter annihilation affects the ionization history of the universe. In this paper, we update our previous simulation code for calculating the ionization history with the effect of dark matter annihilation by including Helium interactions and improving the precision of calculations. We give an updated constraint on the annihilation cross section and mass of dark matter using the modified RECFAST code with the Planck 2018 datasets.