PT Journal
AU Oldengott, IM
   Barenboim, G
   Kahlen, S
   Salvado, J
   Schwarz, DJ
TI How to relax the cosmological neutrino mass bound
SO Journal of Cosmology and Astroparticle Physics
JI J. Cosmol. Astropart. Phys.
PY 2019
BP 049
EP 18pp
VL 04
IS 4
DI 10.1088/1475-7516/2019/04/049
LA English
DE neutrino masses from cosmology; cosmological neutrinos; cosmological parameters from CMBR; cosmological parameters from LSS
AB We study the impact of non-standard momentum distributions of cosmic neutrinos on the anisotropy spectrum of the cosmic microwave background and the matter power spectrum of the large scale structure. We show that the neutrino distribution has almost no unique observable imprint, as it is almost entirely degenerate with the effective number of neutrino flavours, N-eff, and the neutrino mass, m(nu). Performing a Markov chain Monte Carlo analysis with current cosmological data, we demonstrate that the neutrino mass bound heavily depends on the assumed momentum distribution of relic neutrinos. The message of this work is simple and has to our knowledge not been pointed out clearly before: cosmology allows that neutrinos have larger masses if their average momentum is larger than that of a perfectly thermal distribution. Here we provide an example in which the mass limits are relaxed by a factor of two.
ER