Exploring Sterile Neutrino Decays in the Adolescent Universe

The early universe provides a unique opportunity for researching neutrinos because in these dense and hot places, neutrinos have significant interactions with each other and everything else in the plasma of the early universe. One issue in the current cosmological paradigm is the lithium problem, where there is a discrepancy between predicted versus observed abundances of lithium produced during Big Bang Nucleosynthesis. In this talk, we look beyond the Standard Model to try and address this discrepancy by using the early universe as a laboratory to study the decay of sterile neutrinos into Standard model particles and its effect on cosmological observables. These decays create nonthermal neutrino spectra as opposed to nearly thermal spectra predicted by standard cosmology. These altered spectra affect the production of primordial elements during BBN and the formation of large scale structure.