Speaker
Description
GW170817 and SN1987A were the events of the century which opened a window to multi-messenger astronomy and astrophysics. There is a growing consensus that the MHD-Jet supernova and collapsar dominate the heavy r-element production over the entire history of cosmic evolution, and the neutron-star merger contribution delays due to cosmologically long time-delay for slow GW radiation [1,2]. We will first discuss when and how these astrophysical events contribute to the element production in Galactic chemical evolution [3]. We have recently found that the i- and s-processes could occur in the r-process site of collapsar nucleosynthesis [2]. We will propose nuclear experiments to measure the neutron-capture cross sections relevant for the collapsar i-process [4]. These explosive phenomena emit extremely large flux of energetic neutrinos that provide unique nucleosynthetic signals for flavor conversions at high density. We will discuss the neutrino-flavor conversions induced by collective and MSW effects at high density and propose a new astrophysical method to constrain still unknown neutrino mass hierarchy [5,6]. If our theoretical prediction would be verified by precise meteorite analysis of SiC X grains, this could be a piece of evidence constraining still unknown neutrino mass hierarchy, which is complementary to laboratory experiments on vacuum oscillation [7].
[1] C. Kobayashi, A. Karakas, M. Lugaro, ApJ 900 (2020), 179.
[2] Z. He, T. Kajino, M. Kusakabe, et al., ApJ Lett 966 (2024), L37.
[3] Y. Yamazaki, Z. He, T. Kajino, et al., ApJ 933 (2022), 112.
[4] Z. He, T. Kajino, et al., to be published (2025).
[5] H. Ko, D. Jang, M. Cheoun, et al. with T. Kajino, ApJ 937 (2022), 116.
[6] H. Sasaki, Y. Yamazaki, T. Kajino, et al., ApJ 924 (2022), 29; PL B851 (2024), 138581.
[7] X. Yao, T. Kajino, Y. Luo, et al., to be published in ApJ (2025).
