Big bang nucleosynthesis, matter-antimatter regions, extra relativistic species, and relic gravitational waves

  title={Big bang nucleosynthesis, matter-antimatter regions, extra relativistic species, and relic gravitational waves},
  author={Massimo Giovannini and Elina Keihanen and Hannu Kurki-Suonio},
  journal={Physical Review D},
Provided that matter-antimatter domains are present at the onset of big bang nucleosynthesis (BBN), the number of allowed additional relativistic species increases, compared to the standard scenario when matter-antimatter domains are absent. The extra relativistic species may take the form of massless fermions or even massless bosons, like relic gravitons. The number of additional degrees of freedom compatible with BBN depends, in this framework, upon the typical scale of the domains and the… 
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