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arXiv · hep-ph/9505319

Big Bang Nucleosynthesis in Crisis?

N. Hata·R. J. Scherrer·G. Steigman·D. Thomas·T. P. Walker·S. Bludman·P. Langacker
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Abstract

A new evaluation of the constraint on the number of light neutrino species (N_nu) 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 +/- 0.004 (1 sigma) 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 parameterization, the best fit to the combined data is N_nu = 2.1 +/- 0.3 (1 sigma) and the upper limit is N_nu < 2.6 (95% C.L.). The data are inconsistent with the Standard Model (N_nu = 3) at the 98.6% C.L.

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N. Hata, R. J. Scherrer, G. Steigman, D. Thomas, T. P. Walker, S. Bludman, P. Langacker. 1995-11-07. Big Bang Nucleosynthesis in Crisis?. https://doi.org/10.1103/physrevlett.75.3977

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