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arXiv · 1608.02062

The primordial helium abundance and the number of neutrino families

Antonio Peimbert·Manuel Peimbert·Valentina Luridiana
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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 $Y_P = 0.2446\pm0.0029$. 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 $N_{eff} = 2.90\pm0.22$, and a neutron mean life $\tau_{\nu} = 872\pm14(s)$.

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Antonio Peimbert, Manuel Peimbert, Valentina Luridiana. 2016-08-06. The primordial helium abundance and the number of neutrino families. https://arxiv.org/abs/1608.02062

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