Exploring the Neutrino Mass Hierarchy from Isotopic Ratios of Supernova Nucleosynthesis Products in Presolar Grains

Abstract

We study the nucleosynthesis in a core-collapse supernova model including newly calculated neutrino-induced reaction rates with both collective and Mikheyev-Smirnov-Wolfenstein (MSW) neutrino-flavor oscillations considered. We show that the measurement of a pair of ${}^{11}$B/${}^{10}$B and ${}^{138}$La/${}^{139}$La or ${}^6$Li/${}^7$Li and ${}^{138}$La/${}^{139}$La in presolar grains that are inferred to have originated from core-collapse supernovae could constrain the neutrino mass hierarchy. The new shell-model and the model of quasi-particle random phase approximation in the estimate of three important neutrino-induced reactions, $\nu {+}^{16}$O, $\nu {+}^{20}$Ne, and $\nu {+}^{138}$Ba are applied in our reaction network. The new rates decrease the calculated ${}^7$Li/${}^6$Li ratio by a factor of five compared with the previous study. More interestingly, these new rates result in a clear separation of the isotopic ratio of ${}^{11}$B/${}^{10}$B between normal and inverted mass hierarchies in the O/Ne, O/C, and C/He layers where ${}^{138}$La abundance depends strongly on the mass hierarchy. In these layers, the sensitivity of the calculated abundances of ${}^{10,11}$B and ${}^{6,7}$Li to the nuclear reaction uncertainties is also tiny. Therefore, we propose that the ${}^{11}$B/${}^{10}$B vs. ${}^{138}$La/${}^{139}$La and ${}^6$Li/${}^7$Li vs. ${}^{138}$La/${}^{139}$La in type X silicon carbide grains sampled material from C/He layer can be used as a new probe to constrain the neutrino mass hierarchy.

Comments: 21 pages, 4 figures, accepted by ApJ