2014/04/30 by Ryotaro Ichimasa, R. Ichimasa, Riou Nakamura +4
Physics and Astronomy · #Astrophysics #Baryon #Big Bang nucleosynthesis #Cosmology and Gravitation Theories #Dark Matter and Cosmic Phenomena #Degeneracy (biology) #Degenerate energy levels #Deuterium #Neutrino #Nuclear physics #Nuclear reaction #Nucleosynthesis #Particle physics #Particle physics theoretical and experimental studies #Physics #Quantum mechanics #astro-ph.CO
paper · pdf · doi:10.1103/physrevd.90.023527
published as Physical Review D, volume 90, eid 023527, 2014 · 4 figures
openalex publication_date 2014/07/21 · arxiv created 2014/08/04 · arxiv updated 2014/08/05 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Comparing the latest observed abundances of 4He and D, we make a \ensuremathχ2 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 4He 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 4He and D: the baryon-to-photon ratio in units of 10^\ensuremath-10 is found to be in the range 6.02\ensuremath\lesssim\ensuremathη10\ensuremath\lesssim6.54 for the specified parameters of neutrino degeneracy.