Microscopic structure of the Gamow-Teller resonance in 58Cu

The Gamow-Teller (GT) states in 58Cu have been studied via the 58Ni(3He,t+p) and 58Ni(3He,t+γ) coincidence experiments. The GT states in 58Cu at Ex=6-12 MeV, where both T=1 and T=2,1+ states exist, are excited strongly in the 58Ni(3He,t) reaction at E(3He)=450 MeV and θ=0 deg. Proton emissions from the GT states in 58Cu to the hole states in 57Ni have been observed with solid-state detectors in coincidence with high energy tritons measured with a magnetic spectrometer. For the first time, the γ-ray emissions from the excited states in 58Cu and in 57Ni, following the 58Ni(3He,t+p) reaction at intermediate energies, have also been observed in coincidence with tritons. Strengths of proton decay into several neutron-hole states in 57Ni and γ-decay strengths are used to discuss the wave functions of the GT states in 58Cu. The T=1 and T=2 GT states do only weakly decay into a T=3/2,f7/2-1 neutron-hole state at 5.230 MeV in 57Ni, which is strongly excited via the 58Ni(p,d)57Ni reaction. The wave functions of the T=1 and T=2 GT states with the f7/2-1 neutron-hole configuration are inferred to be strongly coupled to 2p-2h configurations, making fragmented GT strengths in 58Cu