Big-bang nucleosynthesis in comparison with observed helium and deuterium abundances: Possibility of a nonstandard model

R. Ichimasa, R. Nakamura, M. Hashimoto, K. Arai

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Comparing the latest observed abundances of He4 and D, we make a χ2 analysis to see whether it is possible to reconcile primordial nucleosynthesis using the up-to-date nuclear data of NACRE II and the mean life of neutrons. If we adopt the observational data of He4 by Izotov et al. [Astron. Astrophys. 558, A57 (2013)], we find that it is impossible to get a reasonable agreement with the standard big-bang nucleosynthesis. However, by including degenerate neutrinos, we succeed in obtaining consistent constraints between the neutrino degeneracy and the baryon-to-photon ratio from a detailed comparison of calculated abundances with the observational data of He4 and D: the baryon-to-photon ratio in units of 10-10 is found to be in the range 6.02η10 6.54 for the specified parameters of neutrino degeneracy.

Original languageEnglish
Article number023527
JournalPhysical Review D - Particles, Fields, Gravitation and Cosmology
Volume90
Issue number2
DOIs
Publication statusPublished - Jul 21 2014

All Science Journal Classification (ASJC) codes

  • Nuclear and High Energy Physics
  • Physics and Astronomy (miscellaneous)

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