Neutrino-nucleus reactions for nucleosynthesis

We calculated neutrino-induced reactions in the energy range below the quasi-elastic region for nuclei of astrophysical importance. Neutrino-induced reactions have been found to be important for nucleosynthesis in core collapsing supernovae because the expected neutrino flux is sufficiently high enough to excite many relevant nuclei in spite of the small cross section of the weak interaction. Our calculation is carried out with the Quasi-particle Random Phase Approximation (QRPA), which has been successfully applied for the nuclear β and double β decay of relevant nuclei. Our QRPA takes neutron-proton as well as neutron-neutron and proton-proton pairing correlations into account. To describe neutrino reactions, general multipole transitions by the weak interaction with finite momentum transfers are calculated for neutral and charged current reactions. Both reactions are described in a theoretical framework. Our results, which are compared with other theoretical calculations, are shown to well reproduce the sparse experimental data, in specific, for ¹²C and ⁵⁶Fe targets. Therefore our results for ⁴⁰Ar, ⁵⁶Ni, ¹³⁸La and ¹⁸⁰Ta targets could be valuable data for predicting yields of future measurements of neutrino-induced reactions and further applications to the neutrino-process in the nucleosynthesis.