1995/05/31 by Naoya Hata, N. Hata, Robert J. Scherrer +11
Physics and Astronomy · #Abundance (ecology) #Abundance of the chemical elements #Astronomy #Astrophysics #Big Bang (financial markets) #Big Bang nucleosynthesis #Cosmology and Gravitation Theories #Gamma-ray bursts and supernovae #Neutrino #Neutrino Physics Research #Nuclear physics #Nucleosynthesis #Physics #Sigma #Stars #astro-ph #hep-ph
paper · pdf · doi:10.1103/physrevlett.75.3977
published as Phys.Rev.Lett.75:3977-3980,1995 · To be published in Phys. Rev. Lett. Revised version to reflect referee comments and criticisms by Copi, Schramm, and Turner of robustness of D/He-3 analysis. Small quantitative changes but qualitative conclusions unchanged. Question mark added to title. Entire ps file available at ftp://upenn5.hep.upenn.edu/pub/hata/papers/bbn.ps.Z See also astro-ph/9412087
arxiv created 1995/11/07 · openalex publication_date 1995/11/27 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
A new evaluation of the constraint on the number of light neutrino species (N_\ensuremathν) from big bang nucleosynthesis suggests a discrepancy between the predicted light element abundances and those inferred from observations, unless the inferred primordial 4He abundance has been underestimated by 0.014\ifmmode±\else\textpm\fi0.004 (1\ensuremathσ) or less than 10% (95% C.L.) of 3He survives stellar processing. With the quoted systematic errors in the observed abundances and a conservative chemical evolution parametrization, the best fit to the combined data is N_\ensuremathν=2.1\ifmmode±\else\textpm\fi0.3 (1\ensuremathσ) and the upper limit is N_\ensuremathν<2.6 (95% C.L.). The data are inconsistent with the standard model (N_\ensuremathν=3) at the 98.6% C.L.