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

The neutrino-nucleus reaction cross sections of He-4 and C-12 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 Li-7 and B-11 produced during the supernova explosion of a 16.2 M-circle dot star model compared to the case using the conventional cross sections by about 10%. On the other hand, the yield of B-10 decreases by a factor of 2. The yields of Li-6, Be-9, and the radioactive nucleus Be-10 are found at a level of similar to 10(-11) M-circle dot. The temperature of v(mu,tau)- and (v) over bar (mu,tau)- neutrinos inferred from the supernova contribution of B-11 in Galactic chemical evolution models is constrained to the 4.3-6.5 MeV range. The increase in the Li-7 and B-11 yields due to neutrino oscillations is demonstrated with the new cross sections.