Neutrino-Induced Reactions on Ni and Fe Isotopes and Nucleosynthesis in Stars

Neutrino-induced reactions on Ni and Fe isotopes are investigated based on new shell model Hamiltonians for $fp$-shell, GXPF1. Spin and magnetic properties of nuclei have been considerably improved by the Hamiltonians, where important roles of tensor interaction on shell evolutions are properly taken into account. Charge-exchange reactions on $^{56}$Fe induced by DAR neutrinos is investigated by using Gamow-Teller strength obtained by the new Hamiltonian, GXPF1J. The observed cross section is shown to be consistent with the observation. The Gamow-Teller strength in $^{56}$Ni is found to be more spread compared to previous calculations and result in a considerably large branching ratio for the proton knock-out channel. This leads to the enhancement of the production yields of heavy elements such as $^{55}$Mn and $^{59}$Co in population III stars for the new Hamiltonian [1]. The electron capture reactions on $^{56}$Ni, neutrino-induced reactions on $^{52}$Fe and the production of elements such as $^{51}$V in supernovae will be also discussed. \\[4pt] [1] T. Suzuki et al., Phys. Rec. C79, 061603(R) (2009).