Resonant Production of Sterile Neutrinos in the Early Universe

We examine the cosmological impacts of a light resonantly produced sterile neutrino in the early universe. Such a neutrino could be produced through lepton number-driven Mikheyev-Smirnov-Wolfenstein conversion of active neutrinos, resulting in a non-thermal spectrum of both sterile and active neutr...

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Bibliographic Details
Main Author: Gilbert, Lauren Ann
Published: 2016
Online Access: Gilbert, Lauren Ann (2016) Resonant Production of Sterile Neutrinos in the Early Universe. Senior thesis (Major), California Institute of Technology. doi:10.7907/BKTV-8H10. https://resolver.caltech.edu/CaltechTHESIS:01102018-100325254 <https://resolver.caltech.edu/CaltechTHESIS:01102018-100325254>
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Summary:We examine the cosmological impacts of a light resonantly produced sterile neutrino in the early universe. Such a neutrino could be produced through lepton number-driven Mikheyev-Smirnov-Wolfenstein conversion of active neutrinos, resulting in a non-thermal spectrum of both sterile and active neutrinos. If this process occurs during weak decoupling and big bang nucleosynthesis, it would affect the electron neutrino flux and therefore the n/p ratio. This allows us to use observations of primordial helium (Y<sub>p</sub>), primordial deuterium (D/H), and N<sub>eff</sub> to place limits on this process.