Open AccessConstraints on the relic neutrino abundance and implications for cosmological neutrino mass limits
Author(s) -
Nicole F. Bell
Publication year - 2004
Language(s) - English
Resource type - Reports
DOI - 10.2172/879071
Subject(s) - neutrino , physics , particle physics , measurements of neutrino speed , lepton , solar neutrino problem , cosmic neutrino background , neutrino oscillation , boson , physics beyond the standard model , solar neutrino , astrophysics , nuclear physics , electron
The authors examine a mechanism which can lead to flavor transformation of neutrino-antineutrino asymmetries in the early universe, a process which is unavoidable when the neutrino mixing angles are large. This sets the best limit on the lepton number of the universe, and hence on the relic neutrino abundance. They also consider the consequences for the relic neutrino abundance if extra neutrino interactions are allowed, e.g., the coupling of the neutrinos to a light (compared to m{sub {nu}}) boson. For a wide range of couplings not excluded by other considerations, the relic neutrinos would annihilate to bosons at late times, and thus make a negligible contribution to the matter density today. This mechanism evades the neutrino mass limits arising from large scale structure