http://arxiv.org/abs/2206.00693
The recent measurement of helium-4 from the near-infrared spectroscopy of extremely metal-poor galaxies by the Subaru Survey may point to a new puzzle in the Early Universe. We exploit this new helium measurement together with the percent-level determination of primordial deuterium, to assess indications for a non-vanishing lepton asymmetry during the Big Bang Nucleosynthesis (BBN) era, paying particular attention to the role of uncertainties in the nuclear reaction network. A cutting-edge Bayesian analysis of BBN data jointly with information from the Cosmic Microwave Background suggests the existence of a nonzero lepton asymmetry at around the 2$\sigma$ level, providing a hint for cosmology beyond $\Lambda$CDM. We discuss conditions for a large total lepton asymmetry to be consistently realized in the Early Universe.
A. Burns, T. Tait and M. Valli
Fri, 3 Jun 22
23/57
Comments: 5 pages, 2 figures, 1 table … comments are welcome!
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