Neutrino Mass Hierarchy from Supernova Nucleosynthesis of Light Elements and the Roles of Unstable Nuclei
Speaker: Xingqun Yao
Abstract:
The origin of neutrino mass and mass hierarchy is one of the biggest unanswered questions in physics. In this talk I propose an astrophysical method so that the supernova (SN) ν-process nucleosynthesis, which is consistent with the mass hierarchy constrained from various ν-oscillation experiments, should provide independent observational signals of nucleosynthetic products in the specific nuclei such as 138La, 19F, 7Li, 11B and others (so-called νnuclei) through the ν-flavor oscillation due to the MSW matter effect and the effect of collective oscillation [1].
Core-collapse SNe emits a huge number of neutrinos which bring valuable observational information on how the neutrinos propagate through the high-density matter and change their flavors and how explosive nucleosynthesis occurs. We found that the still unknown mass hierarchy is imprinted in the nucleosynthetic products of ν-nuclei [1,2]. In this talk, I will discuss the mechanism of SN ν-process nucleosynthesis and try to constrain the mass hierarchy by comparing our theoretical prediction of nuclear abundances and observed values in the meteorites and spectrascopy study. Among the calculated results, the abundance ratios of 11B/138La and 19F/16Oprovide exclusively sensitive probes to neutrino mass hierarchy [1]. These ratios are also influenced by the mass cut during the ejection phase of SN materials. These facts provide valuable quantitative tools to constrain the mass hierarchy through precise measurements of nuclear abundances of these ν-nuclei in SiC-X pre-solar grains and comprehensive studies of solar-system abundances.