Are cosmological neutrinos free-streaming?
Astrophysics
2009-11-13 v1
Abstract
Precision data from cosmology suggest neutrinos stream freely and hence interact very weakly around the epoch of recombination. We study this issue in a simple framework where neutrinos recouple instantaneously and stop streaming freely at a redshift z_i. The latest cosmological data imply z_i < 1500, the exact constraint depending somewhat on the assumed prior on z_i. This bound translates into a limit on the coupling strength between neutrinos and majoron-like particles phi, implying tau > 1 x 10^10 s (m_2/50 meV)^3 for the decay nu_2 -> nu_1+phi.
Cite
@article{arxiv.0806.1735,
title = {Are cosmological neutrinos free-streaming?},
author = {Anders Basboll and Ole Eggers Bjaelde and Steen Hannestad and Georg G. Raffelt},
journal= {arXiv preprint arXiv:0806.1735},
year = {2009}
}
Comments
4 pages, 2 figures