The Cosmic Neutrino Background and the age of the Universe
نویسندگان
چکیده
We discuss the cosmological degeneracy between the age of the Universe, the Hubble parameter and the effective number of relativistic particles Neff . We show that independent determinations of the Hubble parameter H(z) such as those recently provided by [1], combined with other cosmological data sets can provide the most stringent constraints on Neff , yielding Neff = 3.7 +1.1 −1.2 at 95% confidence level. A neutrino background is detected with high significance: Neff > 1.8 at better than 99% confidence level. Constraints on the age of the Universe in the framework of an extra background of relativistic particles are improved by a factor 3.
منابع مشابه
Looking for cosmic neutrino background
*Correspondence: Chiaki Yanagisawa, Department of Physics and Astronomy, Stony Brook University, NY 11794-3800, USA e-mail: chiaki@ nngroup.physics.sunysb.edu Since the discovery of neutrino oscillation in atmospheric neutrinos by the Super-Kamiokande experiment in 1998, study of neutrinos has been one of exciting fields in high-energy physics. All the mixing angles were measured. Quests for (1...
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