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MeV-scale reheating temperature and cosmological production of light sterile neutrinos

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  • Takuya Hasegawa, KEK, High Energy Accelerator Research Organization (KEK), Theory Ctr, IPNS, Graduate University for Advanced Studies (Sokendai)
  • ,
  • Nagisa Hiroshima, KEK, High Energy Accelerator Research Organization (KEK), Theory Ctr, IPNS, University of Toyama
  • ,
  • Kazunori Kohri, Graduate University for Advanced Studies, University of Tokyo, KEK, High Energy Accelerator Research Organization (KEK), Theory Ctr, IPNS
  • ,
  • Rasmus S. L. Hansen, Max-Planck-Institut für Kernphysik, Niels Bohr Institute
  • ,
  • Thomas Tram
  • Steen Hannestad

We investigate how sterile neutrinos with a range of masses influence cosmology in MeV-scale reheating temperature scenarios. By computing the production of sterile neutrinos through the combination of mixing and scattering in the early Universe, we find that light sterile neutrinos, with masses and mixings as inferred from short-baseline neutrino oscillation experiments, are consistent with big-bang nucleosynthesis (BBN) and cosmic microwave background (CMB) radiation for the reheating temperature of (1) MeV if the parent particle responsible for reheating decays into electromagnetic components (radiative decay). In contrast, if the parent particle mainly decays into hadrons (hadronic decay), the bound from BBN becomes more stringent. In this case, the existence of the light sterile neutrinos can be cosmologically excluded, depending on the mass and the hadronic branching ratio of the parent particle.

Original languageEnglish
Article number015
JournalJournal of Cosmology and Astroparticle Physics
Number of pages26
Publication statusPublished - Aug 2020

    Research areas

  • Big bang nucleosynthesis, Cosmology of theories beyond the SM, Particle physics-cosmology connection, Physics of the early universe

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