Neutrinos and the Dark Matter Problem

• Published in: Philosophical transactions of the Royal Society of London. Series A: Mathematical, physical, and engineering sciences physical, and engineering sciences, 1994-01, Vol.346 (1678), p.121-135
• Main Author: Frenk, Carlos S.
• Format: Article
• Language: English
• Subjects: Amplitude; Average linear density; Cold dark matter; Dark matter; Galaxies; Galaxy formation; Neutrino masses; Neutrinos; Particle interactions; Physics
• ISSN: 1364-503X; 0962-8428; 1471-2962; 2054-0299
• DOI: 10.1098/rsta.1994.0013

Theoretical and experimental arguments suggest that the mean mass density of our universe is close to the closure value and that most of the mass in the universe consists of weakly interacting non-baryonic particles. Among the plethora of candidates that have been proposed as the dark matter, the neutrino remains the only particle known to exist, even though the issue of a neutrino mass remains unresolved. It was shown several years ago that neutrinos alone cannot provide the dark matter because physical processes in the early universe would have wiped out primordial density fluctuations on the scale of galaxies and below. The idea that cosmic strings or textures may seed galaxy formation in a neutrino-dominated universe has not yet been demonstrated to be viable. On the other hand, a model in which the bulk of the dark matter is cold and neutrinos with a mass of ca. 10 eV provide a ca. 30% contribution can, in principle, overcome many of the objections against the standard cold dark matter cosmogony. Although subject to the usual `fine-tuning' criticism, these mixed dark matter models represent the best cosmological argument in favour of a non-zero rest mass for the neutrino.