Isospin structure of J= 1+ states in 58Ni and 58Cu studied by 58Ni(p,p') and 58Ni(3He,t)58Cu measurements

Isospin is a good quantum number under the assumption that the nuclear interaction is charge independent. An analogous structure of excited states is expected for nuclei with the same mass number A but with different z components Tz of the isospin T, where Tz=(N-Z)/2. The analogous structure has been studied for the isobaric nuclei 58Ni and 58Cu by comparing the transitions from the 58Ni ground state (initial isospin Ti=1 and J=0+) to the M1 and the Gamow-Teller (GT) states (J=1+) in 58Ni and 58Cu, respectively. For this purpose, proton inelastic scattering (p,p') at Ep=160 MeV and the charge-exchange (3He,t) reaction at 140 MeV/nucleon were both measured at 0°, exciting final states with isospin Tf=1 and 2 and Tf=0, 1, and 2, respectively. High energy and scattering-angle resolutions were achieved by applying complete beam matching techniques. On the basis of the correspondence between excitation energies and transition strengths, isospin values Tf=1 and 2 of analog GT and M1 states were identified. The distribution of Tf=2 states was also compared with results of 58Ni(d,2He), 58Ni(t,3He), and 58Ni(n,p) experiments, in which only Tf=2 states are excited. The obtained GT strength distribution is compared with the results of shell-model calculations.

Isospin structure of J= 1+ states in 58Ni and 58Cu studied by 58Ni(p,p') and 58Ni(3He,t)58Cu measurements Academic Article