Speaker
Description
GW170817/SSS17a was an event of the century that opened a new window to multi-messenger astronomy and nuclear astrophysics. Optical and near-infrared emissions among many other observables suggest that their total energy release is consistent with radiative decays of r-process nuclei predicted theoretically although no specific r-process element was identified. Core-collapse supernovae (both MHD Jet-SNe and ν-SNe) are viable candidates for the r-process. MHD Jet-SNe explain the “universality” in the observed elemental r-process abundance pattern in metal poor stars. Neutron star merger (NSM), on the other hand, could not contribute to the early Galaxy for cosmologically long merging time-scale for slow GW radiation. Nevertheless, NSM is still a possible explanation for the solar-system r-process abundance. We propose a novel solution to this twisted problem by carrying out NSM and SN r-process nucleosynthesis calculations with Galactic chemo-dynamical evolution [1-4].
We also discuss the impact of SN nucleosynthesis on the physics of neutrino oscillations. The elements at A = 80-100 originate from many processes such as r-, s-, rp-, γ-, ν-, νp-processes [5,6]. We find that νp-process operates strongly with amounts of free neutrons being supplied even on proton-rich (Ye > 0.5) condition via p(ν, e+)n reactions when one takes account of the effects of collective neutrino oscillations [7]. Reaction flows can reach the production of abundant p-nuclei 94Mo, 96Ru, etc. This nucleosynthetic method turns out to be a unique probe indicating still unknown neutrino-mass hierarchy.
[1] S. Shibagaki, T. Kajino, G. J. Mathews et al., ApJ 816 (2016), 79.
[2] T. Kajino & G. J. Mathews, Rep. Prog. Phys. 80 (2017), 084901.
[3] Y. Hirai, T. Kajino et al., ApJ 814 (2015), 41; MNRAS 466 (2017), 2472-2487.
[4] T. Kajino et al., Prog. Part. Nucl. Phys. (2018), in press.
[5] T. Kajino, G. J. Mathews & T. Hayakawa, J. Phys. G41 (2014), 044007.
[6] T. Hayakawa, T. Kajino et al., Phys. Rev. Lett. 121 (2018), 102701.
[7] H. Sasaki, T. Kajino, T. Takiwaki et al., Phys. Rev. D96 (2017), 043013.
