The primordial helium abundance and the number of neutrino families

Abstract

Based on observations of HII regions and the new computations of the recombination coefficients of the He I lines by Porter et al. (2013) we obtain a primordial helium abundance by mass of $Y_P=0.2446\pm 0.0029$. We consider thirteen sources of error for the $Y_P$ determination, some of them are mainly due to systematic effects, while the rest are mainly due to statistical effects. We compare our results with other determinations of $Y_P$ present in the literature. Combining our $Y_P$ value with computations of primordial nucleosynthesis we find a number of neutrino species $N_{eff}=2.90\pm 0.22$, and a neutron mean life ${\tau }_{\nu }=872\pm 14(s)$.

6 pages. Accepted for publication in the Revista Mexicana de Astronomía y Astrofísica

References in corpus (2)

• Probing Dark Energy models with neutrons
• The Primordial Helium Abundance

Cited by in corpus (2)

• Big-Bang Nucleosynthesis After Planck
• The BAO+BBN take on the Hubble tension