Speaker
Description
We propose a new astrophysical method of supernova nucleosynthesis to constrain still unknown neutrino mass hierarchy and discuss the roles of radioactive nuclear reactions. Explosions of single massive stars, i.e. magneto-hydrodynamic-jet supernova (MHD-Jet SN) and collapsar, and binary neutron-star merger are the viable candidate sites for r-process. We will first discuss when and how these astrophysical sites have contributed to the enrichment of the heavy elements in cosmic evolution [1]. We have recently found that the i- and s-processes could occur in the r-process site of collapsar nucleosynthesis [2]. We will present a list of nuclear reactions relevant for these new processes [3]. These explosive phenomena emit extremely large flux of energetic neutrinos that provide unique nucleosynthetic signals of the neutrino-nucleus interactions and flavor conversions at high-density [4,5]. We will, secondly, discuss our recent finding that the collective oscillation and MSW effects at high-density affect strongly the SN nucleosynthesis and the isotopic ratios in SiC X grains could provide a clear signature of constraining still unknown neutrino mass-hierarchy [6].
[1] Y. Yamazaki, Z. He, T. Kajino, et al., Astrophys. J. 933 (2022), 112.
[2] Z. He, T. Kajino, M. Kusakabe, et al., Astrophys. J. Lett. 966 (2024), L37.
[3] Z. He, T. Kajino, Y. Luo, et al., (2025), to be published.
[4] H. Ko, D. Jang, M. Cheoun, et al., Astrophys. J. 937 (2022), 116.
[5] H. Sasaki, Y. Yamazaki, T. Kajino, et al., Phys. Lett. B851 (2024).
[6] X. Yao, T. Kajino, Y. Luo, et al., (2025), to be published
