Lepton epoch

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In physical cosmology, the lepton epoch was the period in the evolution of the early universe in which the leptons dominated the mass of the Universe. It started roughly 1 second after the Big Bang, after the majority of hadrons and anti-hadrons annihilated each other at the end of the hadron epoch.[1] During the lepton epoch, the temperature of the Universe was still high enough to create neutrino and electron-positron pairs. Approximately 10 seconds after the Big Bang, the temperature of the universe had fallen to the point where electron-positron pairs were gradually annihilated.[2] A small residue of electrons needed to charge-neutralize the Universe remained along with free streaming neutrinos: an important aspect of this epoch is the neutrino decoupling.[3] The Big Bang nucleosynthesis epoch follows, overlapping with the photon epoch.[4][5]

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  1. ^ Fromerth, M.J.; Kuznetsova, I.; Labun, L.; Letessier, J.; Rafelski, J. (2012). "From Quark-Gluon Universe to Neutrino Decoupling: 200 < T < 2MeV". Acta Physica Polonica B. 43 (12): 2261. arXiv:1211.4297. doi:10.5506/APhysPolB.43.2261. ISSN 0587-4254. S2CID 118448487.
  2. ^ "Thermal history of the Universe and early growth of density fluctuations" (PDF). Guinevere Kauffmann. Max Planck Institute for Astrophysics. Retrieved 2016-01-06.
  3. ^ Birrell, Jeremiah; Yang, Cheng Tao; Rafelski, Johann (2015). "Relic neutrino freeze-out: Dependence on natural constants". Nuclear Physics B. 890: 481–517. arXiv:1406.1759. Bibcode:2015NuPhB.890..481B. doi:10.1016/j.nuclphysb.2014.11.020.
  4. ^ "First few minutes". Eric Chaisson. Harvard Smithsonian Center for Astrophysics. Retrieved 2016-01-06.
  5. ^ "Timeline of the Big Bang". The physics of the Universe. Retrieved 2016-01-06.