Extended analysis of neutrino-dark matter interactions with small-scale CMB experiments

We explore an extension of the standard ACDM model by including an interaction between neutrinos and dark matter, and making use of the ground based telescope data of the Cosmic Microwave Background (CMB) from the Atacama Cosmology Telescope (ACT). An indication for a non-zero coupling between dark matter and neutrinos (both assuming a temperature independent and T2 dependent cross-section) is obtained at the 1a level coming from the ACT CMB data alone and when combined with the Planck CMB and Baryon Acoustic Oscillations (BAO) measurements. This result is confirmed by both fixing the effective number of relativistic degrees of freedom in the early Universe to the Standard Model value of Neff = 3.044, and allowing Neff to be a free cosmological parameter. Furthermore, when performing a Bayesian model comparison, the interacting vDM (+Neff) scenario is mostly preferred over a baseline ACDM (+Neff) cosmology. The preferred value is then used as a benchmark and the potential implications of dark matter's interaction with a sterile neutrino are discussed. (c) 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Automated summary

This study explores the interaction between dark matter and neutrinos by analyzing the Cosmic Microwave Background (CMB) data. The results indicate a non-zero coupling between dark matter and neutrinos and confirm the validity of the model. The interacting vDM (+Neff) scenario is found to be preferred over the baseline ACDM (+Neff) cosmology.