Neutrino-nucleus reaction cross sections for light element synthesis in supernova explosions

The neutrino-nucleus reaction cross sections Of ⁴He and ¹²C are evaluated using new shell model Hamiltonians. Branching ratios of various decay channels are calculated to evaluate the yields of Li, Be, and B produced through the v-process in supernova explosions. The new cross sections enhance the yields of ⁷Li and ¹¹B produced during the supernova explosion of a 16.2 M_⊙ star model compared to the case using the conventional cross sections by about 10%. On the other hand, the yield of ¹⁰B decreases by a factor of 2. The yields of ⁶Li, ⁹Be, and the radioactive nucleus ¹⁰Be are found at a level of ∼10^-11 M_⊙. The temperature of v_μτ- and v̄_μ,τ , -neutrinos inferred from the supernova contribution of ¹¹B in Galactic chemical evolution models is constrained to the 4.3-6.5 MeV range. The increase in the ⁷Li and ¹¹B yields due to neutrino oscillations is demonstrated with the new cross sections.