Key points are not available for this paper at this time.
We provide updated bounds on non-standard neutrino interactions based on data from the Planck satellite as well as auxiliary cosmological measurements. Two types of models are studied - A Fermi-like 4-point interaction and an interaction mediated by a light pseudoscalar - and we show that these two models are representative of models in which neutrinos either decouple or recouple in the early Universe. Current cosmological data constrain the effective 4-point coupling to be GX (0. 1 \, GeV) ^-2, corresponding to GX 1. 0 10⁷ GF. For non-standard pseudoscalar interactions we set a limit on the diagonal elements of the dimensionless coupling matrix, g₈₉, of g₈₈ 1. 2 10^-7. For the off-diagonal elements which induce neutrino decay the bound is significantly stronger, corresponding to g₈₉ 2. 4 10^-11 (m/0. 05 \, eV) ^-2, or a lifetime constraint of 0. 8 10^10 \, s \, (m/0. 05 \, eV) ^3 \,. This is currently the strongest known bound on this particular type of neutrino decay. We finally note that extremely strong neutrino self-interactions which completely suppress anisotropic stress are very highly disfavoured by current data (² 10⁴).
Archidiacono et al. (Wed,) studied this question.