Neutrino-Nucleus Reactions at MeV Region based on New Shell-Model Hamiltonians

Abstract

Neutrino‐nucleus reactions at MeV region are evaluated by using new shell model Hamiltonians, which are found to improve the description of spin degrees of freedom in nuclei as well as shell evolutions. The light element synthesis by neutrino processes in supernova explosions is discussed with the use of the new reaction cross sections for 12C and 4He. Possible constraints on the mixing angle θ13 and the neutrino mass hierarchy are pointed out to be imposed by the production yields of 7Li and 11B. Spin‐dipole transition strengths in 16O and neutrino‐induced reactions on 16O are investigated with the new improved Hamiltonian. The Gamow‐Teller transition strength in 56Ni for the new Hamiltonian, which is more fragmented compared to previous calculations, is found to lead to the enhancement of the production yield of 55Mn in population III stars.