Reactions on 40Ar involving solar neutrinos and neutrinos from core-collapsing supernovae

We calculated neutrino reactions on Ar-40 for detecting core-collapsing supernovae (SNe) neutrinos. The nucleus was originally exploited to identify the solar neutrino emitted from B-8 produced in pp chains on the Sun. With the higher energy neutrinos emitted from the core-collapsing SNe, contributions from higher multipole transitions, as well as from the Gamow-Teller and Fermi transitions, are shown to be important ingredients for understanding reactions induced by the SN neutrino. Moreover, higher excited states beyond a few states known in experiment diminish significantly the expected large difference between the cross sections of nu(e) and (nu) over bar (e) reactions on Ar-40, which difference is anticipated because of the large Q value in the (nu) over bar (e) reaction. The reduction is shown to lead to a difference between them of only a factor of 2.