2−Isobaric Analog Resonance in theY89(p, n2)Zr89Reaction and the Excited States ofZr89

The ($p, n$) reaction on ${}_{}{}^{89}{}_{}{}^{}\mathrm{Y}$ has been studied around the $2^{-}$ isobaric analog resonance at the proton energy of 4.807 MeV. Differential cross sections have been measured for the neturon groups which leave ${}_{}{}^{89}{}_{}{}^{}\mathrm{Zr}$ in the ground state and the excited states at 0.592 and 1.096 MeV. Angular distributions of the neutron groups which leave ${}_{}{}^{89}{}_{}{}^{}\mathrm{Zr}$ in the excited states at 1.096, 1.465, and 1.645 MeV have been measured. The results are compared with the predictions of Robson's theory and statistical model.