2020/10/31 by Luis A. Anchordoqui · 1 citation
Physics and Astronomy · #Astrophysics #Biology #Cold dark matter #Context (archaeology) #Cosmology #Cosmology and Gravitation Theories #Dark Matter and Cosmic Phenomena #Dark energy #Dark matter #Hubble's law #Neutrino #Particle physics #Particle physics theoretical and experimental studies #Physics #Planck #astro-ph.CO #hep-ph
paper · pdf · doi:10.1103/physrevd.103.035025
published as Phys. Rev. D 103, 035025 (2021) · 6 pages revote, 1 figure
openalex created_date 2020/10/29 · arxiv created 2020/12/31 · openalex publication_date 2021/02/24 · arxiv updated 2021/03/01 · openalex updated_date 2026/08/06
It has long been known that the sharpened tension between the observed and inferred values of the Hubble constant H0 can be alleviated if a fraction of dark-matter particles of type \ensuremathχ were produced nonthermally in association with photons \ensuremathγ through the decays of a heavy and relatively long-lived state, viz., X\ensuremath→\ensuremathχ\ensuremathγ. It was recently proposed that this model can also resolve the long-standing lithium (also known as 7Li) problem if M=4 MeV and m=0.04 keV, where M and m are, respectively, the masses of X and \ensuremathχ. We confront this proposal with experiment and demonstrate that cold dark matter decaying before recombination cannot resolve the H0 problem. Moreover, we show that the best-case scenario for alleviating the H0 tension within the context of cold dark matter decaying before recombination arises when the particles decay exclusively into dark radiation, while leaving completely unmodified the production of light elements. To this end, we calculate the general functional form describing the number of equivalent light neutrino species \mathrm\ensuremathΔNeff carried by \ensuremathχ. We show that to resolve the H0 tension at the 1\ensuremathσ level, a 55% correction in m is needed and that the required \mathrm\ensuremathΔNeff is excluded at 95% C.L. by Planck data. We argue in favor of a more complex model of dynamical dark matter to relax the H0 tension.