Telling Three from Four Neutrinos with Cosmology

Simple item page
dc.creatorAbazajian, Kevork N.
dc.date2002-05-16
dc.date2002-09-30
dc.date.accessioned2026-07-07T10:31:15Z
dc.date.available2026-07-07T10:31:15Z
dc.descriptionNew results, namely the independent determination of the deuterium abundance in several quasar absorption systems, and the complementary determination of the cosmological baryon density by observations of anisotropies in the cosmic microwave background (CMB), allow for a reevaluation of the constraints on the relativistic particle content of the universe at primordial nucleosynthesis. Expressed in terms of the neutrino energy density, we find 1.7 < N_ν< 3.5 (95% CL). In particular, we show that phenomenological four neutrino models including a sterile state (not participating in SU(2)_L x U(1)_Y interactions) unavoidably thermalize a fourth neutrino, and are highly disfavored in the standard minimal model of primordial nucleosynthesis, if the systematic uncertainty in the primordial helium abundance is small. We describe plausible extensions of the minimal model which evade this constraint.
dc.description17 pages, 2 figures; matches Astropart. Phys. version
dc.identifierhttps://arxiv.org/abs/astro-ph/0205238
dc.identifierhttp://arxiv.org/abs/astro-ph/0205238
dc.identifierAstropart.Phys.19:303-312,2003
dc.identifierdoi:10.1016/S0927-6505(02)00204-9
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/178349
dc.subjectAstrophysics
dc.subjectHigh Energy Physics - Phenomenology
dc.titleTelling Three from Four Neutrinos with Cosmology
dc.typetext

Files

Collections

arXiv