Year: 2024
Type: article
Abstract: The temperature and polarization anisotropies of the cosmic microwave background have been used to set constraints on decaying dark matter models down to keV masses. In this work, we extend these limits down to the sub-keV mass range. Using principal component analysis, we estimate the lower bound on the decay lifetime for a basis of different dark matter masses and Standard Model final states, from which the bound on an arbitrary model can be calculated. We validate our principal component analysis using Markov chain Monte Carlo methods and Planck 2018 data. We perform a separate analysis for models decaying into photons below the hydrogen ionization threshold. We demonstrate that, for these models, the effect of energy deposition can be captured approximately by a single parameter, but the redshift dependence of the effect is very different from higher-energy injections; in particular, the perturbations to cosmic microwave background anisotropies are more sensitive to energy deposited around the time of recombination.
Authors: Clara Xu, Wenzer Qin, Tracy R. Slatyer
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: G1006625179, G2595738051, G2879565611, G3398237449, G4360986921, G4437173897, G4689434848, Graduate Research Fellowship Program (GRFP), G638484911, Kavli Institute for Theoretical Physics, Programs on Critical Problems in Physics, Astrophysics and Biophysics at the Aspen Center for Physics, G8751405378, G97843138
OpenAlex ID: W4405529293