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We investigate the neutrino flavor change effects due to neutrino self-interaction and shock wave propagation, as well as the matter effects on the neutrino process in core-collapsing supernovae (CCSNe). For the hydrodynamics, we use two models: a simple thermal bomb model and a specified hydrodynamics model for SN1987A. For the presupernova model, we take an updated model, adjusted to explain SN1987A, which employs recent developments in the (n, γ) reaction rates for nuclei near the stability line (A ∼ 100). As for the neutrino luminosity, we adopt two different models: equivalent neutrino luminosity and nonequivalent luminosity models. The latter is taken from a synthetic analysis of CCSN simulation data, which quantitatively presented the results obtained by various neutrino transport models. Relevant neutrino-induced reaction rates are calculated using a shell model for light nuclei and a quasiparticle random phase approximation model for heavy nuclei. For each model, we present abundances of the light nuclei (7Li, 7Be, 11B, and 11C) and the heavy nuclei (92Nb, 98Tc, 138La, and 180Ta) produced by the neutrino process. The light nuclei abundances turn out to be sensitive to the Mikheyev–Smirnov–Wolfenstein (MSW) region around O-Ne-Mg layer while the heavy nuclei are mainly produced prior to the MSW region. Through detailed analyses, we find that neutrino self-interaction becomes a key ingredient, in addition to the MSW effect, for understanding the neutrino process and the relevant nuclear abundances. The normal mass hierarchy is shown to be more compatible with the meteorite data. The main nuclear reactions for each nucleus are also investigated in detail.

We propose a correction of the standard Big Bang nucleosynthesis (BBN) scenario to resolve the primordial lithium problem by considering a possibility that the primordial plasma can deviate from the ideal state. In the standard BBN, the primordial plasma is assumed to be ideal, with particles and photons satisfying the Maxwell-Boltzmann and Planck distribution, respectively. We suggest that this assumption of the primordial plasma being ideal might oversimplify the early Universe and cause the lithium problem. We find that a deviation of photon distribution from the Planck distribution, which is parameterised with the help of Tsallis statistics, can resolve the primordial lithium problem when the particle distributions of the primordial plasma still follow the Maxwell-Boltzmann distribution. We discuss how the primordial plasma can be weakly non-ideal in this specific fashion and its effects on the cosmic evolution.

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Adopting the 3 + 1 neutrino mixing parameters by the IceCube and short baseline experiments, we investigate the sterile–active neutrino oscillation effects on the supernova neutrino process. For the sterile neutrino (ν s ), we study two different luminosity models. First, we presume that the ν s does not interact with other particles through the standard interactions apart from the oscillation with the active neutrinos. Second, we consider the ν s directly produced by ν e scattering with the matter. In both cases, we find that the pattern of neutrino oscillations drastically impacts on the ν s in supernova environments. In particular multiple resonances occur, and consequently affect thermal neutrino-induced reaction rates. As a result, 7Li, 7Be, 11B, 11C, 92Nb, 98Tc, and 138La yields in the ν-process change. Among those nuclei, we constrain the 7Li and 11B yields using the analysis of observed SiC X grains. Based on the meteoritic data, we conclude that the second model can be allowed, while the first model is excluded. The viability of the second model depends on the sterile neutrino temperature and the neutrino mass hierarchy.