Massive neutrinos and interacting dark matter look alike through the lens of lensing
Abstract
We demonstrate that the suppression in the lensing power spectrum of the cosmic microwave background (CMB) caused by massive neutrinos can be mimicked by dark matter-baryon interactions at the precision of next-generation CMB experiments. Thus, a determination of neutrino masses from the CMB lensing power spectrum may be compromised. We illustrate the degeneracy for a dark matter-proton cross section $\propto v^{-4}$, which arises in the $t$-channel exchange of an ultralight mediator in the nonrelativistic limit.
Fields of Study & Subjects
Dark Matter and Cosmic Phenomena
Cosmology and Gravitation Theories
Astrophysics and Cosmic Phenomena
Publication details
- Journal / source
- Physical review. D/Physical review. D.
- Publisher
- American Physical Society (APS)
- Volume
- 113
- Issue
- 10
- Publication date
- 20 April 2026
- Language
- EN