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arXiv · 0806.1735

Are cosmological neutrinos free-streaming?

Anders Basboll·Ole Eggers Bjaelde·Steen Hannestad·Georg G. Raffelt
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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.

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Anders Basboll, Ole Eggers Bjaelde, Steen Hannestad, Georg G. Raffelt. 2008-06-10. Are cosmological neutrinos free-streaming?. https://doi.org/10.1103/physrevd.79.043512

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