Kirilova, D.; Panayotova, M.; Chizhov, E. Big Bang Nucleosynthesis Constraints and Indications for Beyond Standard Model Neutrino Physics. Symmetry2024, 16, 53.
Kirilova, D.; Panayotova, M.; Chizhov, E. Big Bang Nucleosynthesis Constraints and Indications for Beyond Standard Model Neutrino Physics. Symmetry 2024, 16, 53.
Kirilova, D.; Panayotova, M.; Chizhov, E. Big Bang Nucleosynthesis Constraints and Indications for Beyond Standard Model Neutrino Physics. Symmetry2024, 16, 53.
Kirilova, D.; Panayotova, M.; Chizhov, E. Big Bang Nucleosynthesis Constraints and Indications for Beyond Standard Model Neutrino Physics. Symmetry 2024, 16, 53.
Abstract
We use Big Bang Nucleosynthesis (BBN) to probe Beyond Standard Model physics in the neutrino sector. Recently the abundances of primordially produced light elements D and He-4 were determined from observations with better accuracy. The good agreement between the theoretically predicted abundances of primordially produced and derived from observations light elements allows to update the BBN constraints on Beyond Standard Models (BSM) physics. We provide numerical analysis of several BSM models of BBN and obtain precise cosmological constraints and indications for new neutrino physics. Namely, we derive more stringent BBN constraints on electron neutrino-sterile neutrino oscillations corresponding to 1% uncertainty of the observational determination of the primordial He-4. The cosmological constraints are obtained both for the case of zero and non-zero initial population of the sterle neutrino state. Then in a degenerate BBN model with neutrino νe↔νs oscillations we analyze the change of the cosmological constraints in case lepton asymmetry L is big enough to suppress oscillations. We obtain constraints on the lepton asymmetry L . We discuss a possible solution to the dark radiation problem in degenerate BBN models with νe↔νs oscillations in case L is large enough to suppress neutrino oscillations during BBN epoch. Interestingly, the required value of L for solving DR problem is close to L indicated by EMPRESS experiment and close to the value of lepton asymmetry necessary to relax Hubble tension.
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